prog8/compiler/res/prog8lib/prog8_lib.asm

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NASM
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; Internal library routines - always included by the compiler
; Generic machine independent 6502 code.
orig_stackpointer .byte 0 ; stores the Stack pointer register at program start
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read_byte_from_address_in_AY_into_A .proc
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sta P8ZP_SCRATCH_W2
sty P8ZP_SCRATCH_W2+1
ldy #0
lda (P8ZP_SCRATCH_W2),y
rts
.pend
write_byte_X_to_address_in_AY .proc
sta P8ZP_SCRATCH_W2
sty P8ZP_SCRATCH_W2+1
ldy #0
txa
sta (P8ZP_SCRATCH_W2),y
rts
.pend
reg_less_uw .proc
; AY < P8ZP_SCRATCH_W2?
cpy P8ZP_SCRATCH_W2+1
bcc _true
bne _false
cmp P8ZP_SCRATCH_W2
bcc _true
_false lda #0
rts
_true lda #1
rts
.pend
reg_less_w .proc
; -- AY < P8ZP_SCRATCH_W2?
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cmp P8ZP_SCRATCH_W2
tya
sbc P8ZP_SCRATCH_W2+1
bvc +
eor #$80
+ bmi _true
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lda #0
rts
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_true lda #1
rts
.pend
reg_lesseq_uw .proc
; AY <= P8ZP_SCRATCH_W2?
cpy P8ZP_SCRATCH_W2+1
beq +
bcc _true
lda #0
rts
+ cmp P8ZP_SCRATCH_W2
bcc _true
beq _true
lda #0
rts
_true lda #1
rts
.pend
reg_lesseq_w .proc
; -- P8ZP_SCRATCH_W2 <= AY ? (note: order different from other routines)
cmp P8ZP_SCRATCH_W2
tya
sbc P8ZP_SCRATCH_W2+1
bvc +
eor #$80
+ bpl +
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lda #0
rts
+ lda #1
rts
.pend
memcopy16_up .proc
; -- copy memory UP from (P8ZP_SCRATCH_W1) to (P8ZP_SCRATCH_W2) of length X/Y (16-bit, X=lo, Y=hi)
; clobbers register A,X,Y
source = P8ZP_SCRATCH_W1
dest = P8ZP_SCRATCH_W2
length = P8ZP_SCRATCH_B1 ; (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 (P8ZP_SCRATCH_W1), length XY, with value in A.
; clobbers X, Y
stx P8ZP_SCRATCH_B1
sty _save_reg
ldy #0
ldx _save_reg
beq _lastpage
_fullpage sta (P8ZP_SCRATCH_W1),y
iny
bne _fullpage
inc P8ZP_SCRATCH_W1+1 ; next page
dex
bne _fullpage
_lastpage ldy P8ZP_SCRATCH_B1
beq +
- dey
sta (P8ZP_SCRATCH_W1),y
bne -
+ rts
_save_reg .byte 0
.pend
memsetw .proc
; -- fill memory from (P8ZP_SCRATCH_W1) number of words in P8ZP_SCRATCH_W2, 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 P8ZP_SCRATCH_W1
stx P8ZP_SCRATCH_B1
ldx P8ZP_SCRATCH_W1+1
inx
stx P8ZP_SCRATCH_REG ; second page
ldy #0
ldx P8ZP_SCRATCH_W2+1
beq _lastpage
_fullpage
_mod1 lda #0 ; self-modified
sta (P8ZP_SCRATCH_W1),y ; first page
sta (P8ZP_SCRATCH_B1),y ; second page
iny
_mod1b lda #0 ; self-modified
sta (P8ZP_SCRATCH_W1),y ; first page
sta (P8ZP_SCRATCH_B1),y ; second page
iny
bne _fullpage
inc P8ZP_SCRATCH_W1+1 ; next page pair
inc P8ZP_SCRATCH_W1+1 ; next page pair
inc P8ZP_SCRATCH_B1+1 ; next page pair
inc P8ZP_SCRATCH_B1+1 ; next page pair
dex
bne _fullpage
_lastpage ldx P8ZP_SCRATCH_W2
beq _done
ldy #0
-
_mod2 lda #0 ; self-modified
sta (P8ZP_SCRATCH_W1), y
inc P8ZP_SCRATCH_W1
bne _mod2b
inc P8ZP_SCRATCH_W1+1
_mod2b lda #0 ; self-modified
sta (P8ZP_SCRATCH_W1), y
inc P8ZP_SCRATCH_W1
bne +
inc P8ZP_SCRATCH_W1+1
+ dex
bne -
_done rts
.pend
ror2_mem_ub .proc
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; -- in-place 8-bit ror of byte at memory location in AY
sta P8ZP_SCRATCH_W1
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sty P8ZP_SCRATCH_W1+1
ldy #0
lda (P8ZP_SCRATCH_W1),y
lsr a
bcc +
ora #$80
+ sta (P8ZP_SCRATCH_W1),y
rts
.pend
rol2_mem_ub .proc
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; -- in-place 8-bit rol of byte at memory location in AY
sta P8ZP_SCRATCH_W1
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sty P8ZP_SCRATCH_W1+1
ldy #0
lda (P8ZP_SCRATCH_W1),y
cmp #$80
rol a
sta (P8ZP_SCRATCH_W1),y
rts
.pend
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strcpy .proc
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; copy a string (must be 0-terminated) from A/Y to (P8ZP_SCRATCH_W1)
; it is assumed the target string is large enough.
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; returns the length of the string that was copied in Y.
sta P8ZP_SCRATCH_W2
sty P8ZP_SCRATCH_W2+1
ldy #$ff
- iny
lda (P8ZP_SCRATCH_W2),y
sta (P8ZP_SCRATCH_W1),y
bne -
rts
.pend
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strcmp_expression .proc
; -- compare strings, result in A
lda _arg_s2
ldy _arg_s2+1
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sta P8ZP_SCRATCH_W2
sty P8ZP_SCRATCH_W2+1
lda _arg_s1
ldy _arg_s1+1
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jmp strcmp_mem
_arg_s1 .word 0
_arg_s2 .word 0
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.pend
strcmp_mem .proc
; -- compares strings in s1 (AY) and s2 (P8ZP_SCRATCH_W2).
; Returns -1,0,1 in A, depeding on the ordering. Clobbers Y.
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sta P8ZP_SCRATCH_W1
sty P8ZP_SCRATCH_W1+1
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ldy #0
_loop lda (P8ZP_SCRATCH_W1),y
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bne +
lda (P8ZP_SCRATCH_W2),y
bne _return_minusone
beq _return
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+ cmp (P8ZP_SCRATCH_W2),y
bcc _return_minusone
bne _return_one
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inc P8ZP_SCRATCH_W1
bne +
inc P8ZP_SCRATCH_W1+1
+ inc P8ZP_SCRATCH_W2
bne _loop
inc P8ZP_SCRATCH_W2+1
bne _loop
_return_one
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lda #1
_return rts
_return_minusone
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lda #-1
rts
.pend
strlen .proc
; -- returns the number of bytes in the string in AY, in Y. Clobbers A.
sta P8ZP_SCRATCH_W1
sty P8ZP_SCRATCH_W1+1
ldy #0
- lda (P8ZP_SCRATCH_W1),y
beq +
iny
bne -
+ rts
.pend
containment_bytearray .proc
; -- check if a value exists in a byte array.
; parameters: P8ZP_SCRATCH_W1: address of the byte array, A = byte to check, Y = length of array (>=1).
; returns boolean 0/1 in A.
dey
- cmp (P8ZP_SCRATCH_W1),y
beq +
dey
cpy #255
bne -
lda #0
rts
+ lda #1
rts
.pend
containment_wordarray .proc
; -- check if a value exists in a word array.
; parameters: P8ZP_SCRATCH_W1: value to check, P8ZP_SCRATCH_W2: address of the word array, Y = length of array (>=1).
; returns boolean 0/1 in A.
dey
tya
asl a
tay
- lda P8ZP_SCRATCH_W1
cmp (P8ZP_SCRATCH_W2),y
bne +
lda P8ZP_SCRATCH_W1+1
iny
cmp (P8ZP_SCRATCH_W2),y
beq _found
dey
+ dey
dey
cpy #254
bne -
lda #0
rts
_found lda #1
rts
.pend