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Merge pull request #115 from greg-king5/cc65-mul

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Add a signed 8-bit times 8-bit multiply function.
This commit is contained in:
Oliver Schmidt 2014-05-12 15:34:32 +02:00
commit 0a40b7d420
7 changed files with 117 additions and 24 deletions
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22
libsrc/common/cc65_imul8x8r16.s Normal file
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@ -0,0 +1,22 @@
;
; 2014-03-27, Oliver Schmidt
; 2014-05-08, Greg King
;
; CC65 library: 8x8 => 16 signed multiplication
;
.export _cc65_imul8x8r16
.import imul8x8r16, popa, ptr1:zp
;---------------------------------------------------------------------------
; 8x8 => 16 signed multiplication routine.
.proc _cc65_imul8x8r16
sta ptr1
jsr popa
jmp imul8x8r16
.endproc

4
libsrc/common/cc65_umul8x8r16.s
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@ -5,9 +5,7 @@
;
.export _cc65_umul8x8r16
.import umul8x8r16, popa
.include "zeropage.inc"
.import umul8x8r16, popa, ptr1:zp
;---------------------------------------------------------------------------

4
libsrc/runtime/imul16x16r32.s
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@ -13,9 +13,9 @@
;---------------------------------------------------------------------------
; 16x16 => 32 signed multiplication routine.
;
; lhs rhs result result also in
; LHS RHS result result also in
; -------------------------------------------------------------
; ptr1 ax ax:sreg
; ax ptr1 ax:sreg
;
; There is probably a faster way to do this.
;

75
libsrc/runtime/imul8x8r16.s Normal file
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@ -0,0 +1,75 @@
;
; 2010-11-02, Ullrich von Bassewitz
; 2014-05-10, Greg King
;
; CC65 runtime: 8x8 => 16 signed multiplication
;
.export imul8x8r16, imul8x8r16m
.importzp ptr1, ptr3, tmp1
.macpack generic
;---------------------------------------------------------------------------
; 8x8 => 16 signed multiplication routine.
;
; multiplicand multiplier product
; LHS RHS result
; -------------------------------------------------------------
; .A (ptr3-low) ptr1-low .XA
;
imul8x8r16:
sta ptr3
imul8x8r16m:
ldx #>0
bit ptr3
bpl @L7
dex
@L7: stx ptr3+1 ; Extend sign of Left-Hand Side
ldy #<0 ; Clear .XY accumulator
ldx #>0
lda ptr1
bmi NegMult
bpl @L2 ; Branch always
@L0: tya ; Add current multiplicand
add ptr3
tay
txa
adc ptr3+1
tax
@L1: asl ptr3
rol ptr3+1
@L2: lsr ptr1 ; Get next bit of Right-Hand Side into carry
bcs @L0
bnz @L1 ; Loop if more one-bits in multiplier
tya ; Put result into cc65's accumulator
rts
; The multiplier is negative.
; Therefore, make it positive; and, subtract when multiplying.
NegMult:
eor #%11111111
sta ptr1
inc ptr1
bnz @L2 ; Branch always
@L0: tya ; Subtract current multiplicand
sub ptr3
tay
txa
sbc ptr3+1
tax
@L1: asl ptr3
rol ptr3+1
@L2: lsr ptr1 ; Get next bit of Right-Hand Side into carry
bcs @L0
bnz @L1 ; Loop if more one-bits in multiplier
tya ; Put result into cc65's accumulator
rts

12
libsrc/runtime/umul16x16r32.s
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@ -13,14 +13,14 @@
;---------------------------------------------------------------------------
; 16x16 => 32 unsigned multiplication routine. Because the overhead for a
; 16x16 => 16 unsigned multiplication routine is small, we will tag it with
; the matching labels as well.
; the matching labels, as well.
;
; routine lhs rhs result result also in
; routine LHS RHS result result also in
; -----------------------------------------------------------------------
; umul16x16r32 ptr1 ax ax:sreg ptr1:sreg
; umul16x16r32m ptr1 ptr3 ax:sreg ptr1:sreg
; umul16x16r16 ptr1 ax ax ptr1
; umul16x16r16m ptr1 ptr3 ax ptr1
; umul16x16r32 ax ptr1 ax:sreg ptr1:sreg
; umul16x16r32m ptr3 ptr1 ax:sreg ptr1:sreg
; umul16x16r16 ax ptr1 ax ptr1
; umul16x16r16m ptr3 ptr1 ax ptr1
;
; ptr3 is left intact by the routine.
;

10
libsrc/runtime/umul8x16r24.s
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@ -13,14 +13,14 @@
;---------------------------------------------------------------------------
; 8x16 => 24 unsigned multiplication routine. Because the overhead for a
; 8x16 => 16 unsigned multiplication routine is small, we will tag it with
; the matching labels as well.
; the matching labels, as well.
;
; routine lhs rhs result result also in
; routine LHS RHS result result also in
; -----------------------------------------------------------------------
; umul8x16r24 ptr1-lo ax ax:sreg-lo ptr1:sreg-lo
; umul8x16r24m ptr1-lo ptr3 ax:sreg-lo ptr1:sreg-lo
; umul8x16r24 ax ptr1-low ax:sreg-low ptr1:sreg-low
; umul8x16r24m ptr3 ptr1-low ax:sreg-low ptr1:sreg-low
;
; ptr3 ist left intact by the routine.
; ptr3 is left intact by the routine.
;
umul8x16r24:

14
libsrc/runtime/umul8x8r16.s
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@ -1,7 +1,7 @@
;
; Ullrich von Bassewitz, 2010-11-02
;
; CC65 runtime: 8x8 => 16 multiplication
; CC65 runtime: 8x8 => 16 unsigned multiplication
;
.export umul8x8r16, umul8x8r16m
@ -9,11 +9,11 @@
;---------------------------------------------------------------------------
; 8x8 => 16 multiplication routine.
; 8x8 => 16 unsigned multiplication routine.
;
; lhs rhs result result also in
; LHS RHS result result in also
; -------------------------------------------------------------
; ptr1-lo ptr3-lo ax ptr1
; .A (ptr3-low) ptr1-low .XA ptr1
;
umul8x8r16:
@ -21,7 +21,7 @@ umul8x8r16:
umul8x8r16m:
lda #0 ; Clear byte 1
ldy #8 ; Number of bits
lsr ptr1 ; Get first bit of lhs into carry
lsr ptr1 ; Get first bit of RHS into carry
@L0: bcc @L1
clc
adc ptr3
@ -30,8 +30,6 @@ umul8x8r16m:
dey
bne @L0
tax
stx ptr1+1 ; Result in a/x and ptr1
stx ptr1+1 ; Result in .XA and ptr1
lda ptr1 ; Load the result
rts ; Done