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646 lines
12 KiB
NASM
646 lines
12 KiB
NASM
; Prog8 internal Math 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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; some more interesting routines can be found here:
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; http://6502org.wikidot.com/software-math
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; http://codebase64.org/doku.php?id=base:6502_6510_maths
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;
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multiply_bytes .proc
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; -- multiply 2 bytes A and Y, result as byte in A (signed or unsigned)
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sta c64.SCRATCH_ZPB1 ; num1
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sty c64.SCRATCH_ZPREG ; num2
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lda #0
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beq _enterloop
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_doAdd clc
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adc c64.SCRATCH_ZPB1
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_loop asl c64.SCRATCH_ZPB1
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_enterloop lsr c64.SCRATCH_ZPREG
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bcs _doAdd
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bne _loop
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rts
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.pend
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multiply_bytes_16 .proc
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; -- multiply 2 bytes A and Y, result as word in A/Y (unsigned)
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sta c64.SCRATCH_ZPB1
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sty c64.SCRATCH_ZPREG
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stx c64.SCRATCH_ZPREGX
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lda #0
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ldx #8
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lsr c64.SCRATCH_ZPB1
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- bcc +
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clc
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adc c64.SCRATCH_ZPREG
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+ ror a
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ror c64.SCRATCH_ZPB1
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dex
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bne -
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tay
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lda c64.SCRATCH_ZPB1
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ldx c64.SCRATCH_ZPREGX
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rts
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.pend
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multiply_words .proc
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; -- multiply two 16-bit words into a 32-bit result (signed and unsigned)
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; input: A/Y = first 16-bit number, c64.SCRATCH_ZPWORD1 in ZP = second 16-bit number
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; output: multiply_words.result 4-bytes/32-bits product, LSB order (low-to-high)
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sta c64.SCRATCH_ZPWORD2
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sty c64.SCRATCH_ZPWORD2+1
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stx c64.SCRATCH_ZPREGX
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mult16 lda #$00
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sta multiply_words_result+2 ; clear upper bits of product
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sta multiply_words_result+3
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ldx #16 ; for all 16 bits...
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- lsr c64.SCRATCH_ZPWORD1+1 ; divide multiplier by 2
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ror c64.SCRATCH_ZPWORD1
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bcc +
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lda multiply_words_result+2 ; get upper half of product and add multiplicand
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clc
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adc c64.SCRATCH_ZPWORD2
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sta multiply_words_result+2
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lda multiply_words_result+3
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adc c64.SCRATCH_ZPWORD2+1
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+ ror a ; rotate partial product
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sta multiply_words_result+3
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ror multiply_words_result+2
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ror multiply_words_result+1
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ror multiply_words_result
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dex
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bne -
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ldx c64.SCRATCH_ZPREGX
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rts
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multiply_words_result .byte 0,0,0,0
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.pend
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divmod_ub .proc
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; -- divide A by Y, result quotient in Y, remainder in A (unsigned)
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; division by zero will result in quotient = 255 and remainder = original number
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sty c64.SCRATCH_ZPREG
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sta c64.SCRATCH_ZPB1
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stx c64.SCRATCH_ZPREGX
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lda #0
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ldx #8
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asl c64.SCRATCH_ZPB1
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- rol a
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cmp c64.SCRATCH_ZPREG
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bcc +
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sbc c64.SCRATCH_ZPREG
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+ rol c64.SCRATCH_ZPB1
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dex
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bne -
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ldy c64.SCRATCH_ZPB1
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ldx c64.SCRATCH_ZPREGX
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rts
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.pend
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divmod_uw_asm .proc
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; -- divide two unsigned words (16 bit each) into 16 bit results
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; input: c64.SCRATCH_ZPWORD1 in ZP: 16 bit number, A/Y: 16 bit divisor
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; output: c64.SCRATCH_ZPWORD2 in ZP: 16 bit remainder, A/Y: 16 bit division result
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; division by zero will result in quotient = 65535 and remainder = divident
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dividend = c64.SCRATCH_ZPWORD1
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remainder = c64.SCRATCH_ZPWORD2
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result = dividend ;save memory by reusing divident to store the result
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sta _divisor
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sty _divisor+1
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stx c64.SCRATCH_ZPREGX
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lda #0 ;preset remainder to 0
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sta remainder
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sta remainder+1
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ldx #16 ;repeat for each bit: ...
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- asl dividend ;dividend lb & hb*2, msb -> Carry
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rol dividend+1
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rol remainder ;remainder lb & hb * 2 + msb from carry
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rol remainder+1
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lda remainder
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sec
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sbc _divisor ;substract divisor to see if it fits in
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tay ;lb result -> Y, for we may need it later
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lda remainder+1
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sbc _divisor+1
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bcc + ;if carry=0 then divisor didn't fit in yet
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sta remainder+1 ;else save substraction result as new remainder,
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sty remainder
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inc result ;and INCrement result cause divisor fit in 1 times
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+ dex
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bne -
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lda result
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ldy result+1
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ldx c64.SCRATCH_ZPREGX
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rts
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_divisor .word 0
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.pend
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randseed .proc
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; -- reset the random seeds for the byte and word random generators
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; arguments: uword seed in A/Y clobbers A
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; (default starting values are: A=$2c Y=$9e)
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sta randword._seed
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sty randword._seed+1
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clc
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adc #14
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sta randbyte._seed
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rts
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.pend
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randbyte .proc
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; -- 8-bit pseudo random number generator into A
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lda _seed
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beq _eor
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asl a
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beq _done ; if the input was $80, skip the EOR
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bcc _done
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_eor eor #$1d ; xor with magic value see below for possible values
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_done sta _seed
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rts
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_seed .byte $3a
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; possible 'magic' eor bytes are:
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; $1d, $2b, $2d, $4d, $5f, $63, $65, $69
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; $71, $87, $8d, $a9, $c3, $cf, $e7, $f5
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.pend
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randword .proc
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; -- 16 bit pseudo random number generator into AY
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magic_eor = $3f1d
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; possible magic eor words are:
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; $3f1d, $3f81, $3fa5, $3fc5, $4075, $409d, $40cd, $4109
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; $413f, $414b, $4153, $4159, $4193, $4199, $41af, $41bb
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lda _seed
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beq _lowZero ; $0000 and $8000 are special values to test for
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; Do a normal shift
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asl _seed
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lda _seed+1
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rol a
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bcc _noEor
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_doEor ; high byte is in A
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eor #>magic_eor
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sta _seed+1
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lda _seed
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eor #<magic_eor
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sta _seed
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ldy _seed+1
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rts
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_lowZero lda _seed+1
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beq _doEor ; High byte is also zero, so apply the EOR
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; For speed, you could store 'magic' into 'seed' directly
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; instead of running the EORs
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; wasn't zero, check for $8000
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asl a
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beq _noEor ; if $00 is left after the shift, then it was $80
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bcs _doEor ; else, do the EOR based on the carry bit as usual
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_noEor sta _seed+1
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tay
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lda _seed
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rts
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_seed .word $2c9e
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.pend
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mul_byte_3 .proc
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; X + X*2
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lda c64.ESTACK_LO+1,x
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asl a
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clc
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adc 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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mul_word_3 .proc
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; W*2 + W
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lda c64.ESTACK_HI+1,x
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sta c64.SCRATCH_ZPREG
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lda c64.ESTACK_LO+1,x
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asl a
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rol c64.SCRATCH_ZPREG
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clc
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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.SCRATCH_ZPREG
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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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mul_byte_5 .proc
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; X*4 + X
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lda c64.ESTACK_LO+1,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+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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mul_word_5 .proc
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; W*4 + W
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lda c64.ESTACK_HI+1,x
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sta c64.SCRATCH_ZPREG
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lda c64.ESTACK_LO+1,x
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asl a
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rol c64.SCRATCH_ZPREG
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asl a
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rol c64.SCRATCH_ZPREG
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clc
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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.SCRATCH_ZPREG
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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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mul_byte_6 .proc
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; (X*2 + X)*2
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lda c64.ESTACK_LO+1,x
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asl a
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clc
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adc c64.ESTACK_LO+1,x
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asl a
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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_6 .proc
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; (W*2 + W)*2
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lda c64.ESTACK_HI+1,x
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sta c64.SCRATCH_ZPREG
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lda c64.ESTACK_LO+1,x
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asl a
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rol c64.SCRATCH_ZPREG
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clc
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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.SCRATCH_ZPREG
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adc c64.ESTACK_HI+1,x
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asl c64.ESTACK_LO+1,x
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rol 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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mul_byte_7 .proc
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; X*8 - X
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lda c64.ESTACK_LO+1,x
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asl a
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asl a
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asl a
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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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mul_word_7 .proc
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; W*8 - W
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lda c64.ESTACK_HI+1,x
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sta c64.SCRATCH_ZPREG
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lda c64.ESTACK_LO+1,x
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asl a
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rol c64.SCRATCH_ZPREG
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asl a
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rol c64.SCRATCH_ZPREG
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asl a
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rol c64.SCRATCH_ZPREG
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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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lda c64.SCRATCH_ZPREG
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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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mul_byte_9 .proc
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; X*8 + X
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lda c64.ESTACK_LO+1,x
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asl a
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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+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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mul_word_9 .proc
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; W*8 + W
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lda c64.ESTACK_HI+1,x
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sta c64.SCRATCH_ZPREG
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lda c64.ESTACK_LO+1,x
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asl a
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rol c64.SCRATCH_ZPREG
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asl a
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rol c64.SCRATCH_ZPREG
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asl a
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rol c64.SCRATCH_ZPREG
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clc
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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.SCRATCH_ZPREG
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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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mul_byte_10 .proc
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; (X*4 + X)*2
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lda c64.ESTACK_LO+1,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+1,x
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asl a
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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_10 .proc
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; (W*4 + W)*2
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lda c64.ESTACK_HI+1,x
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sta c64.SCRATCH_ZPREG
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lda c64.ESTACK_LO+1,x
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asl a
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rol c64.SCRATCH_ZPREG
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asl a
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rol c64.SCRATCH_ZPREG
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clc
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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.SCRATCH_ZPREG
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adc c64.ESTACK_HI+1,x
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asl c64.ESTACK_LO+1,x
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rol 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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mul_byte_11 .proc
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; (X*2 + X)*4 - X
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lda c64.ESTACK_LO+1,x
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asl a
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clc
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adc c64.ESTACK_LO+1,x
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asl a
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asl a
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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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; mul_word_11 is skipped (too much code)
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mul_byte_12 .proc
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; (X*2 + X)*4
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lda c64.ESTACK_LO+1,x
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asl a
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clc
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adc c64.ESTACK_LO+1,x
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asl a
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asl a
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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_12 .proc
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; (W*2 + W)*4
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lda c64.ESTACK_HI+1,x
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sta c64.SCRATCH_ZPREG
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lda c64.ESTACK_LO+1,x
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asl a
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rol c64.SCRATCH_ZPREG
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clc
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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.SCRATCH_ZPREG
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adc c64.ESTACK_HI+1,x
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asl c64.ESTACK_LO+1,x
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rol a
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asl c64.ESTACK_LO+1,x
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rol 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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mul_byte_13 .proc
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; (X*2 + X)*4 + X
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lda c64.ESTACK_LO+1,x
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asl a
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clc
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adc c64.ESTACK_LO+1,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+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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; mul_word_13 is skipped (too much code)
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mul_byte_14 .proc
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; (X*8 - X)*2
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lda c64.ESTACK_LO+1,x
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asl a
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asl a
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asl a
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sec
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sbc c64.ESTACK_LO+1,x
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asl a
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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_14 is skipped (too much code)
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mul_byte_15 .proc
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; X*16 - X
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lda c64.ESTACK_LO+1,x
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asl a
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asl a
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asl a
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asl a
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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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mul_word_15 .proc
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; W*16 - W
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lda c64.ESTACK_HI+1,x
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sta c64.SCRATCH_ZPREG
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lda c64.ESTACK_LO+1,x
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asl a
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rol c64.SCRATCH_ZPREG
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asl a
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rol c64.SCRATCH_ZPREG
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asl a
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rol c64.SCRATCH_ZPREG
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asl a
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rol c64.SCRATCH_ZPREG
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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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lda c64.SCRATCH_ZPREG
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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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mul_byte_20 .proc
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; (X*4 + X)*4
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lda c64.ESTACK_LO+1,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+1,x
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asl a
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asl a
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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_20 .proc
|
|
; (W*4 + W)*4
|
|
lda c64.ESTACK_HI+1,x
|
|
sta c64.SCRATCH_ZPREG
|
|
lda c64.ESTACK_LO+1,x
|
|
asl a
|
|
rol c64.SCRATCH_ZPREG
|
|
asl a
|
|
rol c64.SCRATCH_ZPREG
|
|
clc
|
|
adc c64.ESTACK_LO+1,x
|
|
sta c64.ESTACK_LO+1,x
|
|
lda c64.SCRATCH_ZPREG
|
|
adc c64.ESTACK_HI+1,x
|
|
asl c64.ESTACK_LO+1,x
|
|
rol a
|
|
asl c64.ESTACK_LO+1,x
|
|
rol a
|
|
sta c64.ESTACK_HI+1,x
|
|
rts
|
|
.pend
|
|
|
|
mul_byte_25 .proc
|
|
; (X*2 + X)*8 + X
|
|
lda c64.ESTACK_LO+1,x
|
|
asl a
|
|
clc
|
|
adc c64.ESTACK_LO+1,x
|
|
asl a
|
|
asl a
|
|
asl a
|
|
clc
|
|
adc c64.ESTACK_LO+1,x
|
|
sta c64.ESTACK_LO+1,x
|
|
rts
|
|
.pend
|
|
|
|
mul_word_25 .proc
|
|
; W + W*8 + W*16
|
|
lda c64.ESTACK_HI+1,x
|
|
sta c64.SCRATCH_ZPWORD1+1
|
|
lda c64.ESTACK_LO+1,x
|
|
asl a
|
|
rol c64.SCRATCH_ZPWORD1+1
|
|
asl a
|
|
rol c64.SCRATCH_ZPWORD1+1
|
|
asl a
|
|
rol c64.SCRATCH_ZPWORD1+1
|
|
sta c64.SCRATCH_ZPWORD1
|
|
clc
|
|
adc c64.ESTACK_LO+1,x
|
|
sta c64.ESTACK_LO+1,x
|
|
lda c64.SCRATCH_ZPWORD1+1
|
|
adc c64.ESTACK_HI+1,x
|
|
sta c64.ESTACK_HI+1,x
|
|
lda c64.SCRATCH_ZPWORD1
|
|
asl a
|
|
rol c64.SCRATCH_ZPWORD1+1
|
|
clc
|
|
adc c64.ESTACK_LO+1,x
|
|
sta c64.ESTACK_LO+1,x
|
|
lda c64.SCRATCH_ZPWORD1+1
|
|
adc c64.ESTACK_HI+1,x
|
|
sta c64.ESTACK_HI+1,x
|
|
rts
|
|
.pend
|
|
|
|
mul_byte_40 .proc
|
|
; (X*4 + X)*8
|
|
lda c64.ESTACK_LO+1,x
|
|
asl a
|
|
asl a
|
|
clc
|
|
adc c64.ESTACK_LO+1,x
|
|
asl a
|
|
asl a
|
|
asl a
|
|
sta c64.ESTACK_LO+1,x
|
|
rts
|
|
.pend
|
|
|
|
mul_word_40 .proc
|
|
; (W*4 + W)*8
|
|
lda c64.ESTACK_HI+1,x
|
|
sta c64.SCRATCH_ZPREG
|
|
lda c64.ESTACK_LO+1,x
|
|
asl a
|
|
rol c64.SCRATCH_ZPREG
|
|
asl a
|
|
rol c64.SCRATCH_ZPREG
|
|
clc
|
|
adc c64.ESTACK_LO+1,x
|
|
sta c64.ESTACK_LO+1,x
|
|
lda c64.SCRATCH_ZPREG
|
|
adc c64.ESTACK_HI+1,x
|
|
asl c64.ESTACK_LO+1,x
|
|
rol a
|
|
asl c64.ESTACK_LO+1,x
|
|
rol a
|
|
asl c64.ESTACK_LO+1,x
|
|
rol a
|
|
sta c64.ESTACK_HI+1,x
|
|
rts
|
|
.pend
|