mirror of
https://github.com/irmen/prog8.git
synced 2024-10-31 09:08:02 +00:00
2129 lines
42 KiB
NASM
2129 lines
42 KiB
NASM
; Prog8 internal library routines - always included by the compiler
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;
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; Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
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;
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; indent format: TABS, size=8
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init_system .proc
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; -- initializes the machine to a sane starting state
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; Called automatically by the loader program logic.
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; This means that the BASIC, KERNAL and CHARGEN ROMs are banked in,
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; the VIC, SID and CIA chips are reset, screen is cleared, and the default IRQ is set.
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; Also a different color scheme is chosen to identify ourselves a little.
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; Uppercase charset is activated, and all three registers set to 0, status flags cleared.
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sei
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cld
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lda #%00101111
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sta $00
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lda #%00100111
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sta $01
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jsr c64.IOINIT
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jsr c64.RESTOR
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jsr c64.CINT
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lda #6
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sta c64.EXTCOL
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lda #7
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sta c64.COLOR
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lda #0
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sta c64.BGCOL0
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tax
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tay
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clc
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clv
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cli
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rts
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.pend
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read_byte_from_address_on_stack .proc
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; -- read the byte from the memory address on the top of the stack, return in A (stack remains unchanged)
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lda c64.ESTACK_LO+1,x
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ldy c64.ESTACK_HI+1,x
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sta c64.SCRATCH_ZPWORD2
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sty c64.SCRATCH_ZPWORD2+1
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ldy #0
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lda (c64.SCRATCH_ZPWORD2),y
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rts
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.pend
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write_byte_to_address_on_stack .proc
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; -- write the byte in A to the memory address on the top of the stack (stack remains unchanged)
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ldy c64.ESTACK_LO+1,x
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sty c64.SCRATCH_ZPWORD2
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ldy c64.ESTACK_HI+1,x
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sty c64.SCRATCH_ZPWORD2+1
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ldy #0
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sta (c64.SCRATCH_ZPWORD2),y
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rts
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.pend
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add_a_to_zpword .proc
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; -- add ubyte in A to the uword in c64.SCRATCH_ZPWORD1
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clc
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adc c64.SCRATCH_ZPWORD1
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sta c64.SCRATCH_ZPWORD1
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bcc +
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inc c64.SCRATCH_ZPWORD1+1
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+ rts
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.pend
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pop_index_times_5 .proc
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inx
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lda c64.ESTACK_LO,x
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asl a
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asl a
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clc
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adc c64.ESTACK_LO,x
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rts
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.pend
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neg_b .proc
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lda #0
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sec
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sbc c64.ESTACK_LO+1,x
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sta c64.ESTACK_LO+1,x
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rts
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.pend
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neg_w .proc
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sec
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lda #0
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sbc c64.ESTACK_LO+1,x
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sta c64.ESTACK_LO+1,x
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lda #0
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sbc c64.ESTACK_HI+1,x
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sta c64.ESTACK_HI+1,x
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rts
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.pend
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inv_word .proc
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lda c64.ESTACK_LO+1,x
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eor #255
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sta c64.ESTACK_LO+1,x
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lda c64.ESTACK_HI+1,x
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eor #255
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sta c64.ESTACK_HI+1,x
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rts
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.pend
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not_byte .proc
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lda c64.ESTACK_LO+1,x
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beq +
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lda #1
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+ eor #1
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sta c64.ESTACK_LO+1,x
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rts
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.pend
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not_word .proc
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lda c64.ESTACK_LO + 1,x
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ora c64.ESTACK_HI + 1,x
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beq +
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lda #1
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+ eor #1
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sta c64.ESTACK_LO + 1,x
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lsr a
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sta c64.ESTACK_HI + 1,x
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rts
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.pend
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bitand_b .proc
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; -- bitwise and (of 2 bytes)
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lda c64.ESTACK_LO+2,x
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and c64.ESTACK_LO+1,x
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inx
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sta c64.ESTACK_LO+1,x
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rts
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.pend
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bitor_b .proc
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; -- bitwise or (of 2 bytes)
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lda c64.ESTACK_LO+2,x
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ora c64.ESTACK_LO+1,x
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inx
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sta c64.ESTACK_LO+1,x
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rts
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.pend
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bitxor_b .proc
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; -- bitwise xor (of 2 bytes)
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lda c64.ESTACK_LO+2,x
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eor c64.ESTACK_LO+1,x
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inx
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sta c64.ESTACK_LO+1,x
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rts
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.pend
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bitand_w .proc
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; -- bitwise and (of 2 words)
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lda c64.ESTACK_LO+2,x
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and c64.ESTACK_LO+1,x
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sta c64.ESTACK_LO+2,x
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lda c64.ESTACK_HI+2,x
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and c64.ESTACK_HI+1,x
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sta c64.ESTACK_HI+2,x
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inx
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rts
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.pend
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bitor_w .proc
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; -- bitwise or (of 2 words)
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lda c64.ESTACK_LO+2,x
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ora c64.ESTACK_LO+1,x
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sta c64.ESTACK_LO+2,x
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lda c64.ESTACK_HI+2,x
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ora c64.ESTACK_HI+1,x
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sta c64.ESTACK_HI+2,x
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inx
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rts
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.pend
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bitxor_w .proc
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; -- bitwise xor (of 2 bytes)
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lda c64.ESTACK_LO+2,x
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eor c64.ESTACK_LO+1,x
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sta c64.ESTACK_LO+2,x
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lda c64.ESTACK_HI+2,x
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eor c64.ESTACK_HI+1,x
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sta c64.ESTACK_HI+2,x
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inx
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rts
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.pend
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and_b .proc
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; -- logical and (of 2 bytes)
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lda c64.ESTACK_LO+2,x
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beq +
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lda #1
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+ sta c64.SCRATCH_ZPB1
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lda c64.ESTACK_LO+1,x
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beq +
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lda #1
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+ and c64.SCRATCH_ZPB1
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inx
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sta c64.ESTACK_LO+1,x
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rts
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.pend
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or_b .proc
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; -- logical or (of 2 bytes)
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lda c64.ESTACK_LO+2,x
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ora c64.ESTACK_LO+1,x
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beq +
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lda #1
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+ inx
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sta c64.ESTACK_LO+1,x
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rts
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.pend
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xor_b .proc
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; -- logical xor (of 2 bytes)
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lda c64.ESTACK_LO+2,x
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beq +
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lda #1
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+ sta c64.SCRATCH_ZPB1
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lda c64.ESTACK_LO+1,x
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beq +
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lda #1
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+ eor c64.SCRATCH_ZPB1
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inx
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sta c64.ESTACK_LO+1,x
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rts
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.pend
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and_w .proc
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; -- logical and (word and word -> byte)
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lda c64.ESTACK_LO+2,x
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ora c64.ESTACK_HI+2,x
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beq +
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lda #1
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+ sta c64.SCRATCH_ZPB1
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lda c64.ESTACK_LO+1,x
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ora c64.ESTACK_HI+1,x
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beq +
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lda #1
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+ and c64.SCRATCH_ZPB1
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inx
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sta c64.ESTACK_LO+1,x
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sta c64.ESTACK_HI+1,x
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rts
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.pend
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or_w .proc
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; -- logical or (word or word -> byte)
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lda c64.ESTACK_LO+2,x
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ora c64.ESTACK_LO+1,x
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ora c64.ESTACK_HI+2,x
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ora c64.ESTACK_HI+1,x
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beq +
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lda #1
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+ inx
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sta c64.ESTACK_LO+1,x
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sta c64.ESTACK_HI+1,x
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rts
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.pend
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xor_w .proc
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; -- logical xor (word xor word -> byte)
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lda c64.ESTACK_LO+2,x
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ora c64.ESTACK_HI+2,x
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beq +
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lda #1
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+ sta c64.SCRATCH_ZPB1
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lda c64.ESTACK_LO+1,x
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ora c64.ESTACK_HI+1,x
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beq +
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lda #1
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+ eor c64.SCRATCH_ZPB1
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inx
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sta c64.ESTACK_LO+1,x
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sta c64.ESTACK_HI+1,x
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rts
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.pend
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abs_b .proc
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; -- push abs(byte) on stack (as byte)
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lda c64.ESTACK_LO+1,x
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bmi neg_b
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rts
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.pend
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abs_w .proc
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; -- push abs(word) on stack (as word)
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lda c64.ESTACK_HI+1,x
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bmi neg_w
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rts
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.pend
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add_w .proc
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; -- push word+word / uword+uword
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inx
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clc
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lda c64.ESTACK_LO,x
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adc c64.ESTACK_LO+1,x
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sta c64.ESTACK_LO+1,x
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lda c64.ESTACK_HI,x
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adc c64.ESTACK_HI+1,x
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sta c64.ESTACK_HI+1,x
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rts
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.pend
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sub_w .proc
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; -- push word-word
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inx
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sec
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lda c64.ESTACK_LO+1,x
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sbc c64.ESTACK_LO,x
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sta c64.ESTACK_LO+1,x
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lda c64.ESTACK_HI+1,x
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sbc c64.ESTACK_HI,x
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sta c64.ESTACK_HI+1,x
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rts
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.pend
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mul_byte .proc
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; -- b*b->b (signed and unsigned)
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inx
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lda c64.ESTACK_LO,x
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ldy c64.ESTACK_LO+1,x
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jsr math.multiply_bytes
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sta c64.ESTACK_LO+1,x
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rts
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.pend
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mul_word .proc
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inx
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lda c64.ESTACK_LO,x
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sta c64.SCRATCH_ZPWORD1
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lda c64.ESTACK_HI,x
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sta c64.SCRATCH_ZPWORD1+1
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lda c64.ESTACK_LO+1,x
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ldy c64.ESTACK_HI+1,x
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jsr math.multiply_words
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lda math.multiply_words.result
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sta c64.ESTACK_LO+1,x
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lda math.multiply_words.result+1
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sta c64.ESTACK_HI+1,x
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rts
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.pend
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idiv_b .proc
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; signed division: use unsigned division and fix sign of result afterwards
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inx
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lda c64.ESTACK_LO,x
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eor c64.ESTACK_LO+1,x
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php ; save sign of result
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lda c64.ESTACK_LO,x
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bpl +
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eor #$ff
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sec
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adc #0 ; make num1 positive
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+ tay
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inx
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lda c64.ESTACK_LO,x
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bpl +
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eor #$ff
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sec
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adc #0 ; make num2 positive
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+ jsr math.divmod_ub
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sta _remainder
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tya
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plp ; get sign of result
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bpl +
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eor #$ff
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sec
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adc #0 ; negate result
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+ sta c64.ESTACK_LO,x
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dex
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rts
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_remainder .byte 0
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.pend
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idiv_ub .proc
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inx
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ldy c64.ESTACK_LO,x
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lda c64.ESTACK_LO+1,x
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jsr math.divmod_ub
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tya
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sta c64.ESTACK_LO+1,x
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rts
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.pend
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idiv_w .proc
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; signed division: use unsigned division and fix sign of result afterwards
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lda c64.ESTACK_HI+2,x
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eor c64.ESTACK_HI+1,x
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php ; save sign of result
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lda c64.ESTACK_HI+1,x
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bpl +
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jsr neg_w ; make value positive
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+ inx
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lda c64.ESTACK_HI+1,x
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bpl +
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jsr neg_w ; make value positive
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+ lda c64.ESTACK_LO+1,x
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sta c64.SCRATCH_ZPWORD1
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lda c64.ESTACK_HI+1,x
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sta c64.SCRATCH_ZPWORD1+1
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lda c64.ESTACK_LO,x
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ldy c64.ESTACK_HI,x
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jsr math.divmod_uw_asm
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sta c64.ESTACK_LO+1,x
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tya
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sta c64.ESTACK_HI+1,x
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plp
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bpl +
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jmp neg_w ; negate result
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+ rts
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.pend
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idiv_uw .proc
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inx
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lda c64.ESTACK_LO+1,x
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sta c64.SCRATCH_ZPWORD1
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lda c64.ESTACK_HI+1,x
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sta c64.SCRATCH_ZPWORD1+1
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lda c64.ESTACK_LO,x
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ldy c64.ESTACK_HI,x
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jsr math.divmod_uw_asm
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sta c64.ESTACK_LO+1,x
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tya
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sta c64.ESTACK_HI+1,x
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rts
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.pend
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remainder_ub .proc
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inx
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ldy c64.ESTACK_LO,x ; right operand
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lda c64.ESTACK_LO+1,x ; left operand
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jsr math.divmod_ub
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sta c64.ESTACK_LO+1,x
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rts
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.pend
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remainder_uw .proc
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inx
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lda c64.ESTACK_LO+1,x
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sta c64.SCRATCH_ZPWORD1
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lda c64.ESTACK_HI+1,x
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sta c64.SCRATCH_ZPWORD1+1
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lda c64.ESTACK_LO,x
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ldy c64.ESTACK_HI,x
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jsr math.divmod_uw_asm
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lda c64.SCRATCH_ZPWORD2
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sta c64.ESTACK_LO+1,x
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lda c64.SCRATCH_ZPWORD2+1
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sta c64.ESTACK_HI+1,x
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rts
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.pend
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equal_w .proc
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; -- are the two words on the stack identical?
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lda c64.ESTACK_LO+1,x
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cmp c64.ESTACK_LO+2,x
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bne equal_b._equal_b_false
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lda c64.ESTACK_HI+1,x
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cmp c64.ESTACK_HI+2,x
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bne equal_b._equal_b_false
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beq equal_b._equal_b_true
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.pend
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notequal_b .proc
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; -- are the two bytes on the stack different?
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lda c64.ESTACK_LO+1,x
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cmp c64.ESTACK_LO+2,x
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beq equal_b._equal_b_false
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bne equal_b._equal_b_true
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.pend
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notequal_w .proc
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; -- are the two words on the stack different?
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lda c64.ESTACK_HI+1,x
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cmp c64.ESTACK_HI+2,x
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beq notequal_b
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bne equal_b._equal_b_true
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.pend
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less_ub .proc
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lda c64.ESTACK_LO+2,x
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cmp c64.ESTACK_LO+1,x
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bcc equal_b._equal_b_true
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bcs equal_b._equal_b_false
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.pend
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less_b .proc
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; see http://www.6502.org/tutorials/compare_beyond.html
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lda c64.ESTACK_LO+2,x
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sec
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sbc c64.ESTACK_LO+1,x
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bvc +
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eor #$80
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+ bmi equal_b._equal_b_true
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bpl equal_b._equal_b_false
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.pend
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less_uw .proc
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lda c64.ESTACK_HI+2,x
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cmp c64.ESTACK_HI+1,x
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bcc equal_b._equal_b_true
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bne equal_b._equal_b_false
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lda c64.ESTACK_LO+2,x
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cmp c64.ESTACK_LO+1,x
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bcc equal_b._equal_b_true
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bcs equal_b._equal_b_false
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.pend
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less_w .proc
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lda c64.ESTACK_LO+2,x
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cmp c64.ESTACK_LO+1,x
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lda c64.ESTACK_HI+2,x
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sbc c64.ESTACK_HI+1,x
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bvc +
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eor #$80
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+ bmi equal_b._equal_b_true
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bpl equal_b._equal_b_false
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.pend
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equal_b .proc
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; -- are the two bytes on the stack identical?
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lda c64.ESTACK_LO+2,x
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cmp c64.ESTACK_LO+1,x
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bne _equal_b_false
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_equal_b_true lda #1
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_equal_b_store inx
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sta c64.ESTACK_LO+1,x
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rts
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_equal_b_false lda #0
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|
beq _equal_b_store
|
|
.pend
|
|
|
|
lesseq_ub .proc
|
|
lda c64.ESTACK_LO+1,x
|
|
cmp c64.ESTACK_LO+2,x
|
|
bcs equal_b._equal_b_true
|
|
bcc equal_b._equal_b_false
|
|
.pend
|
|
|
|
lesseq_b .proc
|
|
; see http://www.6502.org/tutorials/compare_beyond.html
|
|
lda c64.ESTACK_LO+2,x
|
|
clc
|
|
sbc c64.ESTACK_LO+1,x
|
|
bvc +
|
|
eor #$80
|
|
+ bmi equal_b._equal_b_true
|
|
bpl equal_b._equal_b_false
|
|
.pend
|
|
|
|
lesseq_uw .proc
|
|
lda c64.ESTACK_HI+1,x
|
|
cmp c64.ESTACK_HI+2,x
|
|
bcc equal_b._equal_b_false
|
|
bne equal_b._equal_b_true
|
|
lda c64.ESTACK_LO+1,x
|
|
cmp c64.ESTACK_LO+2,x
|
|
bcs equal_b._equal_b_true
|
|
bcc equal_b._equal_b_false
|
|
.pend
|
|
|
|
lesseq_w .proc
|
|
lda c64.ESTACK_LO+1,x
|
|
cmp c64.ESTACK_LO+2,x
|
|
lda c64.ESTACK_HI+1,x
|
|
sbc c64.ESTACK_HI+2,x
|
|
bvc +
|
|
eor #$80
|
|
+ bpl equal_b._equal_b_true
|
|
bmi equal_b._equal_b_false
|
|
.pend
|
|
|
|
greater_ub .proc
|
|
lda c64.ESTACK_LO+2,x
|
|
cmp c64.ESTACK_LO+1,x
|
|
beq equal_b._equal_b_false
|
|
bcs equal_b._equal_b_true
|
|
bcc equal_b._equal_b_false
|
|
.pend
|
|
|
|
greater_b .proc
|
|
; see http://www.6502.org/tutorials/compare_beyond.html
|
|
lda c64.ESTACK_LO+2,x
|
|
clc
|
|
sbc c64.ESTACK_LO+1,x
|
|
bvc +
|
|
eor #$80
|
|
+ bpl equal_b._equal_b_true
|
|
bmi equal_b._equal_b_false
|
|
.pend
|
|
|
|
greater_uw .proc
|
|
lda c64.ESTACK_HI+1,x
|
|
cmp c64.ESTACK_HI+2,x
|
|
bcc equal_b._equal_b_true
|
|
bne equal_b._equal_b_false
|
|
lda c64.ESTACK_LO+1,x
|
|
cmp c64.ESTACK_LO+2,x
|
|
bcc equal_b._equal_b_true
|
|
bcs equal_b._equal_b_false
|
|
.pend
|
|
|
|
greater_w .proc
|
|
lda c64.ESTACK_LO+1,x
|
|
cmp c64.ESTACK_LO+2,x
|
|
lda c64.ESTACK_HI+1,x
|
|
sbc c64.ESTACK_HI+2,x
|
|
bvc +
|
|
eor #$80
|
|
+ bmi equal_b._equal_b_true
|
|
bpl equal_b._equal_b_false
|
|
.pend
|
|
|
|
greatereq_ub .proc
|
|
lda c64.ESTACK_LO+2,x
|
|
cmp c64.ESTACK_LO+1,x
|
|
bcs equal_b._equal_b_true
|
|
bcc equal_b._equal_b_false
|
|
.pend
|
|
|
|
greatereq_b .proc
|
|
; see http://www.6502.org/tutorials/compare_beyond.html
|
|
lda c64.ESTACK_LO+2,x
|
|
sec
|
|
sbc c64.ESTACK_LO+1,x
|
|
bvc +
|
|
eor #$80
|
|
+ bpl equal_b._equal_b_true
|
|
bmi equal_b._equal_b_false
|
|
.pend
|
|
|
|
greatereq_uw .proc
|
|
lda c64.ESTACK_HI+2,x
|
|
cmp c64.ESTACK_HI+1,x
|
|
bcc equal_b._equal_b_false
|
|
bne equal_b._equal_b_true
|
|
lda c64.ESTACK_LO+2,x
|
|
cmp c64.ESTACK_LO+1,x
|
|
bcs equal_b._equal_b_true
|
|
bcc equal_b._equal_b_false
|
|
.pend
|
|
|
|
greatereq_w .proc
|
|
lda c64.ESTACK_LO+2,x
|
|
cmp c64.ESTACK_LO+1,x
|
|
lda c64.ESTACK_HI+2,x
|
|
sbc c64.ESTACK_HI+1,x
|
|
bvc +
|
|
eor #$80
|
|
+ bpl equal_b._equal_b_true
|
|
bmi equal_b._equal_b_false
|
|
.pend
|
|
|
|
|
|
shiftleft_b .proc
|
|
inx
|
|
ldy c64.ESTACK_LO,x
|
|
bne +
|
|
rts
|
|
+ lda c64.ESTACK_LO+1,x
|
|
- asl a
|
|
dey
|
|
bne -
|
|
sta c64.ESTACK_LO+1,x
|
|
rts
|
|
.pend
|
|
|
|
shiftright_b .proc
|
|
inx
|
|
ldy c64.ESTACK_LO,x
|
|
bne +
|
|
rts
|
|
+ lda c64.ESTACK_LO+1,x
|
|
- lsr a
|
|
dey
|
|
bne -
|
|
sta c64.ESTACK_LO+1,x
|
|
rts
|
|
.pend
|
|
|
|
|
|
orig_stackpointer .byte 0 ; stores the Stack pointer register at program start
|
|
|
|
func_exit .proc
|
|
; -- immediately exit the program with a return code in the A register
|
|
lda c64.ESTACK_LO+1,x
|
|
ldx orig_stackpointer
|
|
txs
|
|
rts ; return to original caller
|
|
.pend
|
|
|
|
|
|
func_read_flags .proc
|
|
; -- put the processor status register on the stack
|
|
php
|
|
pla
|
|
sta c64.ESTACK_LO,x
|
|
dex
|
|
rts
|
|
.pend
|
|
|
|
|
|
func_sqrt16 .proc
|
|
lda c64.ESTACK_LO+1,x
|
|
sta c64.SCRATCH_ZPWORD2
|
|
lda c64.ESTACK_HI+1,x
|
|
sta c64.SCRATCH_ZPWORD2+1
|
|
stx c64.SCRATCH_ZPREGX
|
|
ldy #$00 ; r = 0
|
|
ldx #$07
|
|
clc ; clear bit 16 of m
|
|
_loop
|
|
tya
|
|
ora _stab-1,x
|
|
sta c64.SCRATCH_ZPB1 ; (r asl 8) | (d asl 7)
|
|
lda c64.SCRATCH_ZPWORD2+1
|
|
bcs _skip0 ; m >= 65536? then t <= m is always true
|
|
cmp c64.SCRATCH_ZPB1
|
|
bcc _skip1 ; t <= m
|
|
_skip0
|
|
sbc c64.SCRATCH_ZPB1
|
|
sta c64.SCRATCH_ZPWORD2+1 ; m = m - t
|
|
tya
|
|
ora _stab,x
|
|
tay ; r = r or d
|
|
_skip1
|
|
asl c64.SCRATCH_ZPWORD2
|
|
rol c64.SCRATCH_ZPWORD2+1 ; m = m asl 1
|
|
dex
|
|
bne _loop
|
|
|
|
; last iteration
|
|
bcs _skip2
|
|
sty c64.SCRATCH_ZPB1
|
|
lda c64.SCRATCH_ZPWORD2
|
|
cmp #$80
|
|
lda c64.SCRATCH_ZPWORD2+1
|
|
sbc c64.SCRATCH_ZPB1
|
|
bcc _skip3
|
|
_skip2
|
|
iny ; r = r or d (d is 1 here)
|
|
_skip3
|
|
ldx c64.SCRATCH_ZPREGX
|
|
tya
|
|
sta c64.ESTACK_LO+1,x
|
|
lda #0
|
|
sta c64.ESTACK_HI+1,x
|
|
rts
|
|
_stab .byte $01,$02,$04,$08,$10,$20,$40,$80
|
|
.pend
|
|
|
|
|
|
func_sin8 .proc
|
|
ldy c64.ESTACK_LO+1,x
|
|
lda _sinecos8,y
|
|
sta c64.ESTACK_LO+1,x
|
|
rts
|
|
_sinecos8 .char trunc(127.0 * sin(range(256+64) * rad(360.0/256.0)))
|
|
.pend
|
|
|
|
func_sin8u .proc
|
|
ldy c64.ESTACK_LO+1,x
|
|
lda _sinecos8u,y
|
|
sta c64.ESTACK_LO+1,x
|
|
rts
|
|
_sinecos8u .byte trunc(128.0 + 127.5 * sin(range(256+64) * rad(360.0/256.0)))
|
|
.pend
|
|
|
|
func_sin16 .proc
|
|
ldy c64.ESTACK_LO+1,x
|
|
lda _sinecos8lo,y
|
|
sta c64.ESTACK_LO+1,x
|
|
lda _sinecos8hi,y
|
|
sta c64.ESTACK_HI+1,x
|
|
rts
|
|
|
|
_ := trunc(32767.0 * sin(range(256+64) * rad(360.0/256.0)))
|
|
_sinecos8lo .byte <_
|
|
_sinecos8hi .byte >_
|
|
.pend
|
|
|
|
func_sin16u .proc
|
|
ldy c64.ESTACK_LO+1,x
|
|
lda _sinecos8ulo,y
|
|
sta c64.ESTACK_LO+1,x
|
|
lda _sinecos8uhi,y
|
|
sta c64.ESTACK_HI+1,x
|
|
rts
|
|
|
|
_ := trunc(32768.0 + 32767.5 * sin(range(256+64) * rad(360.0/256.0)))
|
|
_sinecos8ulo .byte <_
|
|
_sinecos8uhi .byte >_
|
|
.pend
|
|
|
|
func_cos8 .proc
|
|
ldy c64.ESTACK_LO+1,x
|
|
lda func_sin8._sinecos8+64,y
|
|
sta c64.ESTACK_LO+1,x
|
|
rts
|
|
.pend
|
|
|
|
func_cos8u .proc
|
|
ldy c64.ESTACK_LO+1,x
|
|
lda func_sin8u._sinecos8u+64,y
|
|
sta c64.ESTACK_LO+1,x
|
|
rts
|
|
.pend
|
|
|
|
func_cos16 .proc
|
|
ldy c64.ESTACK_LO+1,x
|
|
lda func_sin16._sinecos8lo+64,y
|
|
sta c64.ESTACK_LO+1,x
|
|
lda func_sin16._sinecos8hi+64,y
|
|
sta c64.ESTACK_HI+1,x
|
|
rts
|
|
.pend
|
|
|
|
func_cos16u .proc
|
|
ldy c64.ESTACK_LO+1,x
|
|
lda func_sin16u._sinecos8ulo+64,y
|
|
sta c64.ESTACK_LO+1,x
|
|
lda func_sin16u._sinecos8uhi+64,y
|
|
sta c64.ESTACK_HI+1,x
|
|
rts
|
|
.pend
|
|
|
|
|
|
peek_address .proc
|
|
; -- peek address on stack into c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_LO+1,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI+1,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
rts
|
|
.pend
|
|
|
|
func_any_b .proc
|
|
inx
|
|
lda c64.ESTACK_LO,x ; array size
|
|
_entry sta _cmp_mod+1 ; self-modifying code
|
|
jsr peek_address
|
|
ldy #0
|
|
- lda (c64.SCRATCH_ZPWORD1),y
|
|
bne _got_any
|
|
iny
|
|
_cmp_mod cpy #255 ; modified
|
|
bne -
|
|
lda #0
|
|
sta c64.ESTACK_LO+1,x
|
|
rts
|
|
_got_any lda #1
|
|
sta c64.ESTACK_LO+1,x
|
|
rts
|
|
.pend
|
|
|
|
func_any_w .proc
|
|
inx
|
|
lda c64.ESTACK_LO,x ; array size
|
|
asl a ; times 2 because of word
|
|
jmp func_any_b._entry
|
|
.pend
|
|
|
|
func_all_b .proc
|
|
inx
|
|
lda c64.ESTACK_LO,x ; array size
|
|
sta _cmp_mod+1 ; self-modifying code
|
|
jsr peek_address
|
|
ldy #0
|
|
- lda (c64.SCRATCH_ZPWORD1),y
|
|
beq _got_not_all
|
|
iny
|
|
_cmp_mod cpy #255 ; modified
|
|
bne -
|
|
lda #1
|
|
sta c64.ESTACK_LO+1,x
|
|
rts
|
|
_got_not_all lda #0
|
|
sta c64.ESTACK_LO+1,x
|
|
rts
|
|
.pend
|
|
|
|
func_all_w .proc
|
|
inx
|
|
lda c64.ESTACK_LO,x ; array size
|
|
asl a ; times 2 because of word
|
|
sta _cmp_mod+1 ; self-modifying code
|
|
jsr peek_address
|
|
ldy #0
|
|
- lda (c64.SCRATCH_ZPWORD1),y
|
|
bne +
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
bne ++
|
|
lda #0
|
|
sta c64.ESTACK_LO+1,x
|
|
rts
|
|
+ iny
|
|
+ iny
|
|
_cmp_mod cpy #255 ; modified
|
|
bne -
|
|
lda #1
|
|
sta c64.ESTACK_LO+1,x
|
|
rts
|
|
.pend
|
|
|
|
func_max_ub .proc
|
|
jsr pop_array_and_lengthmin1Y
|
|
lda #0
|
|
sta c64.SCRATCH_ZPB1
|
|
- lda (c64.SCRATCH_ZPWORD1),y
|
|
cmp c64.SCRATCH_ZPB1
|
|
bcc +
|
|
sta c64.SCRATCH_ZPB1
|
|
+ dey
|
|
cpy #255
|
|
bne -
|
|
lda c64.SCRATCH_ZPB1
|
|
sta c64.ESTACK_LO,x
|
|
dex
|
|
rts
|
|
.pend
|
|
|
|
func_max_b .proc
|
|
jsr pop_array_and_lengthmin1Y
|
|
lda #-128
|
|
sta c64.SCRATCH_ZPB1
|
|
- lda (c64.SCRATCH_ZPWORD1),y
|
|
sec
|
|
sbc c64.SCRATCH_ZPB1
|
|
bvc +
|
|
eor #$80
|
|
+ bmi +
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
sta c64.SCRATCH_ZPB1
|
|
+ dey
|
|
cpy #255
|
|
bne -
|
|
lda c64.SCRATCH_ZPB1
|
|
sta c64.ESTACK_LO,x
|
|
dex
|
|
rts
|
|
.pend
|
|
|
|
func_max_uw .proc
|
|
lda #0
|
|
sta _result_maxuw
|
|
sta _result_maxuw+1
|
|
jsr pop_array_and_lengthmin1Y
|
|
tya
|
|
asl a
|
|
tay
|
|
_loop
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
dey
|
|
cmp _result_maxuw+1
|
|
bcc _lesseq
|
|
bne _greater
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
cmp _result_maxuw
|
|
bcc _lesseq
|
|
_greater lda (c64.SCRATCH_ZPWORD1),y
|
|
sta _result_maxuw
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
sta _result_maxuw+1
|
|
dey
|
|
_lesseq dey
|
|
dey
|
|
cpy #254
|
|
bne _loop
|
|
lda _result_maxuw
|
|
sta c64.ESTACK_LO,x
|
|
lda _result_maxuw+1
|
|
sta c64.ESTACK_HI,x
|
|
dex
|
|
rts
|
|
_result_maxuw .word 0
|
|
.pend
|
|
|
|
func_max_w .proc
|
|
lda #$00
|
|
sta _result_maxw
|
|
lda #$80
|
|
sta _result_maxw+1
|
|
jsr pop_array_and_lengthmin1Y
|
|
tya
|
|
asl a
|
|
tay
|
|
_loop
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
cmp _result_maxw
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
dey
|
|
sbc _result_maxw+1
|
|
bvc +
|
|
eor #$80
|
|
+ bmi _lesseq
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
sta _result_maxw
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
sta _result_maxw+1
|
|
dey
|
|
_lesseq dey
|
|
dey
|
|
cpy #254
|
|
bne _loop
|
|
lda _result_maxw
|
|
sta c64.ESTACK_LO,x
|
|
lda _result_maxw+1
|
|
sta c64.ESTACK_HI,x
|
|
dex
|
|
rts
|
|
_result_maxw .word 0
|
|
.pend
|
|
|
|
|
|
func_sum_b .proc
|
|
jsr pop_array_and_lengthmin1Y
|
|
lda #0
|
|
sta c64.ESTACK_LO,x
|
|
sta c64.ESTACK_HI,x
|
|
_loop lda (c64.SCRATCH_ZPWORD1),y
|
|
pha
|
|
clc
|
|
adc c64.ESTACK_LO,x
|
|
sta c64.ESTACK_LO,x
|
|
; sign extend the high byte
|
|
pla
|
|
and #$80
|
|
beq +
|
|
lda #$ff
|
|
+ adc c64.ESTACK_HI,x
|
|
sta c64.ESTACK_HI,x
|
|
dey
|
|
cpy #255
|
|
bne _loop
|
|
dex
|
|
rts
|
|
.pend
|
|
|
|
func_sum_ub .proc
|
|
jsr pop_array_and_lengthmin1Y
|
|
lda #0
|
|
sta c64.ESTACK_HI,x
|
|
- clc
|
|
adc (c64.SCRATCH_ZPWORD1),y
|
|
bcc +
|
|
inc c64.ESTACK_HI,x
|
|
+ dey
|
|
cpy #255
|
|
bne -
|
|
sta c64.ESTACK_LO,x
|
|
dex
|
|
rts
|
|
.pend
|
|
|
|
func_sum_uw .proc
|
|
jsr pop_array_and_lengthmin1Y
|
|
tya
|
|
asl a
|
|
tay
|
|
lda #0
|
|
sta c64.ESTACK_LO,x
|
|
sta c64.ESTACK_HI,x
|
|
- lda (c64.SCRATCH_ZPWORD1),y
|
|
iny
|
|
clc
|
|
adc c64.ESTACK_LO,x
|
|
sta c64.ESTACK_LO,x
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
adc c64.ESTACK_HI,x
|
|
sta c64.ESTACK_HI,x
|
|
dey
|
|
dey
|
|
dey
|
|
cpy #254
|
|
bne -
|
|
dex
|
|
rts
|
|
.pend
|
|
|
|
func_sum_w .proc
|
|
jmp func_sum_uw
|
|
.pend
|
|
|
|
|
|
pop_array_and_lengthmin1Y .proc
|
|
inx
|
|
ldy c64.ESTACK_LO,x
|
|
dey ; length minus 1, for iteration
|
|
lda c64.ESTACK_LO+1,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI+1,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
inx
|
|
rts
|
|
.pend
|
|
|
|
func_min_ub .proc
|
|
jsr pop_array_and_lengthmin1Y
|
|
lda #255
|
|
sta c64.SCRATCH_ZPB1
|
|
- lda (c64.SCRATCH_ZPWORD1),y
|
|
cmp c64.SCRATCH_ZPB1
|
|
bcs +
|
|
sta c64.SCRATCH_ZPB1
|
|
+ dey
|
|
cpy #255
|
|
bne -
|
|
lda c64.SCRATCH_ZPB1
|
|
sta c64.ESTACK_LO,x
|
|
dex
|
|
rts
|
|
.pend
|
|
|
|
|
|
func_min_b .proc
|
|
jsr pop_array_and_lengthmin1Y
|
|
lda #127
|
|
sta c64.SCRATCH_ZPB1
|
|
- lda (c64.SCRATCH_ZPWORD1),y
|
|
clc
|
|
sbc c64.SCRATCH_ZPB1
|
|
bvc +
|
|
eor #$80
|
|
+ bpl +
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
sta c64.SCRATCH_ZPB1
|
|
+ dey
|
|
cpy #255
|
|
bne -
|
|
lda c64.SCRATCH_ZPB1
|
|
sta c64.ESTACK_LO,x
|
|
dex
|
|
rts
|
|
.pend
|
|
|
|
func_min_uw .proc
|
|
lda #$ff
|
|
sta _result_minuw
|
|
sta _result_minuw+1
|
|
jsr pop_array_and_lengthmin1Y
|
|
tya
|
|
asl a
|
|
tay
|
|
_loop
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
dey
|
|
cmp _result_minuw+1
|
|
bcc _less
|
|
bne _gtequ
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
cmp _result_minuw
|
|
bcs _gtequ
|
|
_less lda (c64.SCRATCH_ZPWORD1),y
|
|
sta _result_minuw
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
sta _result_minuw+1
|
|
dey
|
|
_gtequ dey
|
|
dey
|
|
cpy #254
|
|
bne _loop
|
|
lda _result_minuw
|
|
sta c64.ESTACK_LO,x
|
|
lda _result_minuw+1
|
|
sta c64.ESTACK_HI,x
|
|
dex
|
|
rts
|
|
_result_minuw .word 0
|
|
.pend
|
|
|
|
func_min_w .proc
|
|
lda #$ff
|
|
sta _result_minw
|
|
lda #$7f
|
|
sta _result_minw+1
|
|
jsr pop_array_and_lengthmin1Y
|
|
tya
|
|
asl a
|
|
tay
|
|
_loop
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
cmp _result_minw
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
dey
|
|
sbc _result_minw+1
|
|
bvc +
|
|
eor #$80
|
|
+ bpl _gtequ
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
sta _result_minw
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
sta _result_minw+1
|
|
dey
|
|
_gtequ dey
|
|
dey
|
|
cpy #254
|
|
bne _loop
|
|
lda _result_minw
|
|
sta c64.ESTACK_LO,x
|
|
lda _result_minw+1
|
|
sta c64.ESTACK_HI,x
|
|
dex
|
|
rts
|
|
_result_minw .word 0
|
|
.pend
|
|
|
|
func_strlen .proc
|
|
; -- push length of 0-terminated string on stack
|
|
jsr peek_address
|
|
ldy #0
|
|
- lda (c64.SCRATCH_ZPWORD1),y
|
|
beq +
|
|
iny
|
|
bne -
|
|
+ tya
|
|
sta c64.ESTACK_LO+1,x
|
|
rts
|
|
.pend
|
|
|
|
func_rnd .proc
|
|
; -- put a random ubyte on the estack
|
|
jsr math.randbyte
|
|
sta c64.ESTACK_LO,x
|
|
dex
|
|
rts
|
|
.pend
|
|
|
|
func_rndw .proc
|
|
; -- put a random uword on the estack
|
|
jsr math.randword
|
|
sta c64.ESTACK_LO,x
|
|
tya
|
|
sta c64.ESTACK_HI,x
|
|
dex
|
|
rts
|
|
.pend
|
|
|
|
|
|
func_memcopy .proc
|
|
; note: clobbers A,Y
|
|
inx
|
|
stx c64.SCRATCH_ZPREGX
|
|
lda c64.ESTACK_LO+2,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI+2,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
lda c64.ESTACK_LO+1,x
|
|
sta c64.SCRATCH_ZPWORD2
|
|
lda c64.ESTACK_HI+1,x
|
|
sta c64.SCRATCH_ZPWORD2+1
|
|
lda c64.ESTACK_LO,x
|
|
tax
|
|
ldy #0
|
|
- lda (c64.SCRATCH_ZPWORD1), y
|
|
sta (c64.SCRATCH_ZPWORD2), y
|
|
iny
|
|
dex
|
|
bne -
|
|
ldx c64.SCRATCH_ZPREGX
|
|
inx
|
|
inx
|
|
rts
|
|
.pend
|
|
|
|
func_memset .proc
|
|
; note: clobbers A,Y
|
|
inx
|
|
stx c64.SCRATCH_ZPREGX
|
|
lda c64.ESTACK_LO+2,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI+2,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
lda c64.ESTACK_LO+1,x
|
|
sta c64.SCRATCH_ZPB1
|
|
ldy c64.ESTACK_HI+1,x
|
|
lda c64.ESTACK_LO,x
|
|
ldx c64.SCRATCH_ZPB1
|
|
jsr memset
|
|
ldx c64.SCRATCH_ZPREGX
|
|
inx
|
|
inx
|
|
rts
|
|
.pend
|
|
|
|
func_memsetw .proc
|
|
; note: clobbers A,Y
|
|
; -- fill memory from (SCRATCH_ZPWORD1) number of words in SCRATCH_ZPWORD2, with word value in AY.
|
|
|
|
inx
|
|
stx c64.SCRATCH_ZPREGX
|
|
lda c64.ESTACK_LO+2,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI+2,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
lda c64.ESTACK_LO+1,x
|
|
sta c64.SCRATCH_ZPWORD2
|
|
lda c64.ESTACK_HI+1,x
|
|
sta c64.SCRATCH_ZPWORD2+1
|
|
lda c64.ESTACK_LO,x
|
|
ldy c64.ESTACK_HI,x
|
|
jsr memsetw
|
|
ldx c64.SCRATCH_ZPREGX
|
|
inx
|
|
inx
|
|
rts
|
|
.pend
|
|
|
|
|
|
memcopy16_up .proc
|
|
; -- copy memory UP from (SCRATCH_ZPWORD1) to (SCRATCH_ZPWORD2) of length X/Y (16-bit, X=lo, Y=hi)
|
|
; clobbers register A,X,Y
|
|
source = c64.SCRATCH_ZPWORD1
|
|
dest = c64.SCRATCH_ZPWORD2
|
|
length = c64.SCRATCH_ZPB1 ; (and SCRATCH_ZPREG)
|
|
|
|
stx length
|
|
sty length+1
|
|
|
|
ldx length ; move low byte of length into X
|
|
bne + ; jump to start if X > 0
|
|
dec length ; subtract 1 from length
|
|
+ ldy #0 ; set Y to 0
|
|
- lda (source),y ; set A to whatever (source) points to offset by Y
|
|
sta (dest),y ; move A to location pointed to by (dest) offset by Y
|
|
iny ; increment Y
|
|
bne + ; if Y<>0 then (rolled over) then still moving bytes
|
|
inc source+1 ; increment hi byte of source
|
|
inc dest+1 ; increment hi byte of dest
|
|
+ dex ; decrement X (lo byte counter)
|
|
bne - ; if X<>0 then move another byte
|
|
dec length ; we've moved 255 bytes, dec length
|
|
bpl - ; if length is still positive go back and move more
|
|
rts ; done
|
|
.pend
|
|
|
|
|
|
memset .proc
|
|
; -- fill memory from (SCRATCH_ZPWORD1), length XY, with value in A.
|
|
; clobbers X, Y
|
|
stx c64.SCRATCH_ZPB1
|
|
sty c64.SCRATCH_ZPREG
|
|
ldy #0
|
|
ldx c64.SCRATCH_ZPREG
|
|
beq _lastpage
|
|
|
|
_fullpage sta (c64.SCRATCH_ZPWORD1),y
|
|
iny
|
|
bne _fullpage
|
|
inc c64.SCRATCH_ZPWORD1+1 ; next page
|
|
dex
|
|
bne _fullpage
|
|
|
|
_lastpage ldy c64.SCRATCH_ZPB1
|
|
beq +
|
|
- dey
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
bne -
|
|
|
|
+ rts
|
|
.pend
|
|
|
|
|
|
memsetw .proc
|
|
; -- fill memory from (SCRATCH_ZPWORD1) number of words in SCRATCH_ZPWORD2, with word value in AY.
|
|
; clobbers A, X, Y
|
|
sta _mod1+1 ; self-modify
|
|
sty _mod1b+1 ; self-modify
|
|
sta _mod2+1 ; self-modify
|
|
sty _mod2b+1 ; self-modify
|
|
ldx c64.SCRATCH_ZPWORD1
|
|
stx c64.SCRATCH_ZPB1
|
|
ldx c64.SCRATCH_ZPWORD1+1
|
|
inx
|
|
stx c64.SCRATCH_ZPREG ; second page
|
|
|
|
ldy #0
|
|
ldx c64.SCRATCH_ZPWORD2+1
|
|
beq _lastpage
|
|
|
|
_fullpage
|
|
_mod1 lda #0 ; self-modified
|
|
sta (c64.SCRATCH_ZPWORD1),y ; first page
|
|
sta (c64.SCRATCH_ZPB1),y ; second page
|
|
iny
|
|
_mod1b lda #0 ; self-modified
|
|
sta (c64.SCRATCH_ZPWORD1),y ; first page
|
|
sta (c64.SCRATCH_ZPB1),y ; second page
|
|
iny
|
|
bne _fullpage
|
|
inc c64.SCRATCH_ZPWORD1+1 ; next page pair
|
|
inc c64.SCRATCH_ZPWORD1+1 ; next page pair
|
|
inc c64.SCRATCH_ZPB1+1 ; next page pair
|
|
inc c64.SCRATCH_ZPB1+1 ; next page pair
|
|
dex
|
|
bne _fullpage
|
|
|
|
_lastpage ldx c64.SCRATCH_ZPWORD2
|
|
beq _done
|
|
|
|
ldy #0
|
|
-
|
|
_mod2 lda #0 ; self-modified
|
|
sta (c64.SCRATCH_ZPWORD1), y
|
|
inc c64.SCRATCH_ZPWORD1
|
|
bne _mod2b
|
|
inc c64.SCRATCH_ZPWORD1+1
|
|
_mod2b lda #0 ; self-modified
|
|
sta (c64.SCRATCH_ZPWORD1), y
|
|
inc c64.SCRATCH_ZPWORD1
|
|
bne +
|
|
inc c64.SCRATCH_ZPWORD1+1
|
|
+ dex
|
|
bne -
|
|
_done rts
|
|
.pend
|
|
|
|
|
|
sort_ub .proc
|
|
; 8bit unsigned sort
|
|
; sorting subroutine coded by mats rosengren (mats.rosengren@esa.int)
|
|
; input: address of array to sort in c64.SCRATCH_ZPWORD1, length in c64.SCRATCH_ZPB1
|
|
; first, put pointer BEFORE array
|
|
lda c64.SCRATCH_ZPWORD1
|
|
bne +
|
|
dec c64.SCRATCH_ZPWORD1+1
|
|
+ dec c64.SCRATCH_ZPWORD1
|
|
_sortloop ldy c64.SCRATCH_ZPB1 ;start of subroutine sort
|
|
lda (c64.SCRATCH_ZPWORD1),y ;last value in (what is left of) sequence to be sorted
|
|
sta c64.SCRATCH_ZPREG ;save value. will be over-written by largest number
|
|
jmp _l2
|
|
_l1 dey
|
|
beq _l3
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
cmp c64.SCRATCH_ZPWORD2+1
|
|
bcc _l1
|
|
_l2 sty c64.SCRATCH_ZPWORD2 ;index of potentially largest value
|
|
sta c64.SCRATCH_ZPWORD2+1 ;potentially largest value
|
|
jmp _l1
|
|
_l3 ldy c64.SCRATCH_ZPB1 ;where the largest value shall be put
|
|
lda c64.SCRATCH_ZPWORD2+1 ;the largest value
|
|
sta (c64.SCRATCH_ZPWORD1),y ;put largest value in place
|
|
ldy c64.SCRATCH_ZPWORD2 ;index of free space
|
|
lda c64.SCRATCH_ZPREG ;the over-written value
|
|
sta (c64.SCRATCH_ZPWORD1),y ;put the over-written value in the free space
|
|
dec c64.SCRATCH_ZPB1 ;end of the shorter sequence still left
|
|
bne _sortloop ;start working with the shorter sequence
|
|
rts
|
|
.pend
|
|
|
|
|
|
sort_b .proc
|
|
; 8bit signed sort
|
|
; sorting subroutine coded by mats rosengren (mats.rosengren@esa.int)
|
|
; input: address of array to sort in c64.SCRATCH_ZPWORD1, length in c64.SCRATCH_ZPB1
|
|
; first, put pointer BEFORE array
|
|
lda c64.SCRATCH_ZPWORD1
|
|
bne +
|
|
dec c64.SCRATCH_ZPWORD1+1
|
|
+ dec c64.SCRATCH_ZPWORD1
|
|
_sortloop ldy c64.SCRATCH_ZPB1 ;start of subroutine sort
|
|
lda (c64.SCRATCH_ZPWORD1),y ;last value in (what is left of) sequence to be sorted
|
|
sta c64.SCRATCH_ZPREG ;save value. will be over-written by largest number
|
|
jmp _l2
|
|
_l1 dey
|
|
beq _l3
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
cmp c64.SCRATCH_ZPWORD2+1
|
|
bmi _l1
|
|
_l2 sty c64.SCRATCH_ZPWORD2 ;index of potentially largest value
|
|
sta c64.SCRATCH_ZPWORD2+1 ;potentially largest value
|
|
jmp _l1
|
|
_l3 ldy c64.SCRATCH_ZPB1 ;where the largest value shall be put
|
|
lda c64.SCRATCH_ZPWORD2+1 ;the largest value
|
|
sta (c64.SCRATCH_ZPWORD1),y ;put largest value in place
|
|
ldy c64.SCRATCH_ZPWORD2 ;index of free space
|
|
lda c64.SCRATCH_ZPREG ;the over-written value
|
|
sta (c64.SCRATCH_ZPWORD1),y ;put the over-written value in the free space
|
|
dec c64.SCRATCH_ZPB1 ;end of the shorter sequence still left
|
|
bne _sortloop ;start working with the shorter sequence
|
|
rts
|
|
.pend
|
|
|
|
|
|
sort_uw .proc
|
|
; 16bit unsigned sort
|
|
; sorting subroutine coded by mats rosengren (mats.rosengren@esa.int)
|
|
; input: address of array to sort in c64.SCRATCH_ZPWORD1, length in c64.SCRATCH_ZPB1
|
|
; first: subtract 2 of the pointer
|
|
asl c64.SCRATCH_ZPB1 ; *2 because words
|
|
lda c64.SCRATCH_ZPWORD1
|
|
sec
|
|
sbc #2
|
|
sta c64.SCRATCH_ZPWORD1
|
|
bcs _sort_loop
|
|
dec c64.SCRATCH_ZPWORD1+1
|
|
_sort_loop ldy c64.SCRATCH_ZPB1 ;start of subroutine sort
|
|
lda (c64.SCRATCH_ZPWORD1),y ;last value in (what is left of) sequence to be sorted
|
|
sta _work3 ;save value. will be over-written by largest number
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
sta _work3+1
|
|
dey
|
|
jmp _l2
|
|
_l1 dey
|
|
dey
|
|
beq _l3
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
dey
|
|
cmp c64.SCRATCH_ZPWORD2+1
|
|
bne +
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
cmp c64.SCRATCH_ZPWORD2
|
|
+ bcc _l1
|
|
_l2 sty _work1 ;index of potentially largest value
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
sta c64.SCRATCH_ZPWORD2 ;potentially largest value
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
sta c64.SCRATCH_ZPWORD2+1
|
|
dey
|
|
jmp _l1
|
|
_l3 ldy c64.SCRATCH_ZPB1 ;where the largest value shall be put
|
|
lda c64.SCRATCH_ZPWORD2 ;the largest value
|
|
sta (c64.SCRATCH_ZPWORD1),y ;put largest value in place
|
|
iny
|
|
lda c64.SCRATCH_ZPWORD2+1
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
ldy _work1 ;index of free space
|
|
lda _work3 ;the over-written value
|
|
sta (c64.SCRATCH_ZPWORD1),y ;put the over-written value in the free space
|
|
iny
|
|
lda _work3+1
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
dey
|
|
dec c64.SCRATCH_ZPB1 ;end of the shorter sequence still left
|
|
dec c64.SCRATCH_ZPB1
|
|
bne _sort_loop ;start working with the shorter sequence
|
|
rts
|
|
_work1 .byte 0
|
|
_work3 .word 0
|
|
.pend
|
|
|
|
|
|
sort_w .proc
|
|
; 16bit signed sort
|
|
; sorting subroutine coded by mats rosengren (mats.rosengren@esa.int)
|
|
; input: address of array to sort in c64.SCRATCH_ZPWORD1, length in c64.SCRATCH_ZPB1
|
|
; first: subtract 2 of the pointer
|
|
asl c64.SCRATCH_ZPB1 ; *2 because words
|
|
lda c64.SCRATCH_ZPWORD1
|
|
sec
|
|
sbc #2
|
|
sta c64.SCRATCH_ZPWORD1
|
|
bcs _sort_loop
|
|
dec c64.SCRATCH_ZPWORD1+1
|
|
_sort_loop ldy c64.SCRATCH_ZPB1 ;start of subroutine sort
|
|
lda (c64.SCRATCH_ZPWORD1),y ;last value in (what is left of) sequence to be sorted
|
|
sta _work3 ;save value. will be over-written by largest number
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
sta _work3+1
|
|
dey
|
|
jmp _l2
|
|
_l1 dey
|
|
dey
|
|
beq _l3
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
cmp c64.SCRATCH_ZPWORD2
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
dey
|
|
sbc c64.SCRATCH_ZPWORD2+1
|
|
bvc +
|
|
eor #$80
|
|
+ bmi _l1
|
|
_l2 sty _work1 ;index of potentially largest value
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
sta c64.SCRATCH_ZPWORD2 ;potentially largest value
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
sta c64.SCRATCH_ZPWORD2+1
|
|
dey
|
|
jmp _l1
|
|
_l3 ldy c64.SCRATCH_ZPB1 ;where the largest value shall be put
|
|
lda c64.SCRATCH_ZPWORD2 ;the largest value
|
|
sta (c64.SCRATCH_ZPWORD1),y ;put largest value in place
|
|
iny
|
|
lda c64.SCRATCH_ZPWORD2+1
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
ldy _work1 ;index of free space
|
|
lda _work3 ;the over-written value
|
|
sta (c64.SCRATCH_ZPWORD1),y ;put the over-written value in the free space
|
|
iny
|
|
lda _work3+1
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
dey
|
|
dec c64.SCRATCH_ZPB1 ;end of the shorter sequence still left
|
|
dec c64.SCRATCH_ZPB1
|
|
bne _sort_loop ;start working with the shorter sequence
|
|
rts
|
|
_work1 .byte 0
|
|
_work3 .word 0
|
|
.pend
|
|
|
|
|
|
reverse_b .proc
|
|
; --- reverse an array of bytes (in-place)
|
|
; inputs: pointer to array in c64.SCRATCH_ZPWORD1, length in A
|
|
_index_right = c64.SCRATCH_ZPWORD2
|
|
_index_left = c64.SCRATCH_ZPWORD2+1
|
|
_loop_count = c64.SCRATCH_ZPREG
|
|
sta _loop_count
|
|
lsr _loop_count
|
|
sec
|
|
sbc #1
|
|
sta _index_right
|
|
lda #0
|
|
sta _index_left
|
|
_loop ldy _index_right
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
pha
|
|
ldy _index_left
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
ldy _index_right
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
pla
|
|
ldy _index_left
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
inc _index_left
|
|
dec _index_right
|
|
dec _loop_count
|
|
bne _loop
|
|
rts
|
|
.pend
|
|
|
|
|
|
reverse_f .proc
|
|
; --- reverse an array of floats
|
|
_left_index = c64.SCRATCH_ZPWORD2
|
|
_right_index = c64.SCRATCH_ZPWORD2+1
|
|
_loop_count = c64.SCRATCH_ZPREG
|
|
pha
|
|
sta c64.SCRATCH_ZPREG
|
|
asl a
|
|
asl a
|
|
clc
|
|
adc c64.SCRATCH_ZPREG ; *5 because float
|
|
sec
|
|
sbc #5
|
|
sta _right_index
|
|
lda #0
|
|
sta _left_index
|
|
pla
|
|
lsr a
|
|
sta _loop_count
|
|
_loop ; push the left indexed float on the stack
|
|
ldy _left_index
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
pha
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
pha
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
pha
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
pha
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
pha
|
|
; copy right index float to left index float
|
|
ldy _right_index
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
ldy _left_index
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
inc _left_index
|
|
inc _right_index
|
|
ldy _right_index
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
ldy _left_index
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
inc _left_index
|
|
inc _right_index
|
|
ldy _right_index
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
ldy _left_index
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
inc _left_index
|
|
inc _right_index
|
|
ldy _right_index
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
ldy _left_index
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
inc _left_index
|
|
inc _right_index
|
|
ldy _right_index
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
ldy _left_index
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
; pop the float off the stack into the right index float
|
|
ldy _right_index
|
|
pla
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
dey
|
|
pla
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
dey
|
|
pla
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
dey
|
|
pla
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
dey
|
|
pla
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
inc _left_index
|
|
lda _right_index
|
|
sec
|
|
sbc #9
|
|
sta _right_index
|
|
dec _loop_count
|
|
bne _loop
|
|
rts
|
|
|
|
.pend
|
|
|
|
|
|
reverse_w .proc
|
|
; --- reverse an array of words (in-place)
|
|
; inputs: pointer to array in c64.SCRATCH_ZPWORD1, length in A
|
|
_index_first = c64.SCRATCH_ZPWORD2
|
|
_index_second = c64.SCRATCH_ZPWORD2+1
|
|
_loop_count = c64.SCRATCH_ZPREG
|
|
pha
|
|
asl a ; *2 because words
|
|
sec
|
|
sbc #2
|
|
sta _index_first
|
|
lda #0
|
|
sta _index_second
|
|
pla
|
|
lsr a
|
|
pha
|
|
sta _loop_count
|
|
; first reverse the lsbs
|
|
_loop_lo ldy _index_first
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
pha
|
|
ldy _index_second
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
ldy _index_first
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
pla
|
|
ldy _index_second
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
inc _index_second
|
|
inc _index_second
|
|
dec _index_first
|
|
dec _index_first
|
|
dec _loop_count
|
|
bne _loop_lo
|
|
; now reverse the msbs
|
|
dec _index_second
|
|
inc _index_first
|
|
inc _index_first
|
|
inc _index_first
|
|
pla
|
|
sta _loop_count
|
|
_loop_hi ldy _index_first
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
pha
|
|
ldy _index_second
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
ldy _index_first
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
pla
|
|
ldy _index_second
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
dec _index_second
|
|
dec _index_second
|
|
inc _index_first
|
|
inc _index_first
|
|
dec _loop_count
|
|
bne _loop_hi
|
|
|
|
rts
|
|
.pend
|
|
|
|
ror2_mem_ub .proc
|
|
; -- in-place 8-bit ror of byte at memory location on stack
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
ldy #0
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
lsr a
|
|
bcc +
|
|
ora #$80
|
|
+ sta (c64.SCRATCH_ZPWORD1),y
|
|
rts
|
|
.pend
|
|
|
|
rol2_mem_ub .proc
|
|
; -- in-place 8-bit rol of byte at memory location on stack
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
ldy #0
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
cmp #$80
|
|
rol a
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
rts
|
|
.pend
|
|
|
|
rol_array_ub .proc
|
|
; -- rol a ubyte in an array (index and array address on stack)
|
|
inx
|
|
ldy c64.ESTACK_LO,x
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
rol a
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
rts
|
|
.pend
|
|
|
|
|
|
ror_array_ub .proc
|
|
; -- ror a ubyte in an array (index and array address on stack)
|
|
inx
|
|
ldy c64.ESTACK_LO,x
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
ror a
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
rts
|
|
.pend
|
|
|
|
ror2_array_ub .proc
|
|
; -- ror2 (8-bit ror) a ubyte in an array (index and array address on stack)
|
|
inx
|
|
ldy c64.ESTACK_LO,x
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
lsr a
|
|
bcc +
|
|
ora #$80
|
|
+ sta (c64.SCRATCH_ZPWORD1),y
|
|
rts
|
|
.pend
|
|
|
|
rol2_array_ub .proc
|
|
; -- rol2 (8-bit rol) a ubyte in an array (index and array address on stack)
|
|
inx
|
|
ldy c64.ESTACK_LO,x
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
cmp #$80
|
|
rol a
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
rts
|
|
.pend
|
|
|
|
ror_array_uw .proc
|
|
; -- ror a uword in an array (index and array address on stack)
|
|
php
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
asl a
|
|
tay
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
plp
|
|
ror a
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
dey
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
ror a
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
rts
|
|
.pend
|
|
|
|
rol_array_uw .proc
|
|
; -- rol a uword in an array (index and array address on stack)
|
|
php
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
asl a
|
|
tay
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
plp
|
|
rol a
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
rol a
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
rts
|
|
.pend
|
|
|
|
rol2_array_uw .proc
|
|
; -- rol2 (16-bit rol) a uword in an array (index and array address on stack)
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
asl a
|
|
tay
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
asl a
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
rol a
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
bcc +
|
|
dey
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
adc #0
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
+ rts
|
|
.pend
|
|
|
|
ror2_array_uw .proc
|
|
; -- ror2 (16-bit ror) a uword in an array (index and array address on stack)
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
asl a
|
|
tay
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
lsr a
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
dey
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
ror a
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
bcc +
|
|
iny
|
|
lda (c64.SCRATCH_ZPWORD1),y
|
|
ora #$80
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
+ rts
|
|
.pend
|
|
|
|
|
|
strcpy .proc
|
|
; copy a string (0-terminated) from A/Y to (ZPWORD1)
|
|
; it is assumed the target string is large enough.
|
|
sta c64.SCRATCH_ZPWORD2
|
|
sty c64.SCRATCH_ZPWORD2+1
|
|
ldy #$ff
|
|
- iny
|
|
lda (c64.SCRATCH_ZPWORD2),y
|
|
sta (c64.SCRATCH_ZPWORD1),y
|
|
bne -
|
|
rts
|
|
.pend
|
|
|
|
|
|
func_leftstr .proc
|
|
; leftstr(source, target, length) with params on stack
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
tay ; length
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
sta c64.SCRATCH_ZPWORD2
|
|
lda c64.ESTACK_HI,x
|
|
sta c64.SCRATCH_ZPWORD2+1
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
lda #0
|
|
sta (c64.SCRATCH_ZPWORD2),y
|
|
- dey
|
|
cpy #$ff
|
|
bne +
|
|
rts
|
|
+ lda (c64.SCRATCH_ZPWORD1),y
|
|
sta (c64.SCRATCH_ZPWORD2),y
|
|
jmp -
|
|
.pend
|
|
|
|
func_rightstr .proc
|
|
; rightstr(source, target, length) with params on stack
|
|
; make place for the 4 parameters for substr()
|
|
dex
|
|
dex
|
|
dex
|
|
dex
|
|
; X-> .
|
|
; x+1 -> length of segment
|
|
; x+2 -> start index
|
|
; X+3 -> target LO+HI
|
|
; X+4 -> source LO+HI
|
|
; original parameters:
|
|
; x+5 -> original length LO
|
|
; x+6 -> original targetLO + HI
|
|
; x+7 -> original sourceLO + HI
|
|
; replicate paramters:
|
|
lda c64.ESTACK_LO+5,x
|
|
sta c64.ESTACK_LO+1,x
|
|
lda c64.ESTACK_LO+6,x
|
|
sta c64.ESTACK_LO+3,x
|
|
lda c64.ESTACK_HI+6,x
|
|
sta c64.ESTACK_HI+3,x
|
|
lda c64.ESTACK_LO+7,x
|
|
sta c64.ESTACK_LO+4,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI+7,x
|
|
sta c64.ESTACK_HI+4,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
; determine string length
|
|
ldy #0
|
|
- lda (c64.SCRATCH_ZPWORD1),y
|
|
beq +
|
|
iny
|
|
bne -
|
|
+ tya
|
|
sec
|
|
sbc c64.ESTACK_LO+1,x ; start index = strlen - segment length
|
|
sta c64.ESTACK_LO+2,x
|
|
jsr func_substr
|
|
; unwind original params
|
|
inx
|
|
inx
|
|
inx
|
|
rts
|
|
.pend
|
|
|
|
func_substr .proc
|
|
; substr(source, target, start, length) with params on stack
|
|
inx
|
|
ldy c64.ESTACK_LO,x ; length
|
|
inx
|
|
lda c64.ESTACK_LO,x ; start
|
|
sta c64.SCRATCH_ZPB1
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
sta c64.SCRATCH_ZPWORD2
|
|
lda c64.ESTACK_HI,x
|
|
sta c64.SCRATCH_ZPWORD2+1
|
|
inx
|
|
lda c64.ESTACK_LO,x
|
|
sta c64.SCRATCH_ZPWORD1
|
|
lda c64.ESTACK_HI,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
; adjust src location
|
|
clc
|
|
lda c64.SCRATCH_ZPWORD1
|
|
adc c64.SCRATCH_ZPB1
|
|
sta c64.SCRATCH_ZPWORD1
|
|
bcc +
|
|
inc c64.SCRATCH_ZPWORD1+1
|
|
+ lda #0
|
|
sta (c64.SCRATCH_ZPWORD2),y
|
|
jmp _startloop
|
|
- lda (c64.SCRATCH_ZPWORD1),y
|
|
sta (c64.SCRATCH_ZPWORD2),y
|
|
_startloop dey
|
|
cpy #$ff
|
|
bne -
|
|
rts
|
|
|
|
.pend
|