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Merge pull request #115 from greg-king5/cc65-mul
Add a signed 8-bit times 8-bit multiply function.
This commit is contained in:
commit
0a40b7d420
22
libsrc/common/cc65_imul8x8r16.s
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22
libsrc/common/cc65_imul8x8r16.s
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@ -0,0 +1,22 @@
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;
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; 2014-03-27, Oliver Schmidt
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; 2014-05-08, Greg King
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;
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; CC65 library: 8x8 => 16 signed multiplication
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;
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.export _cc65_imul8x8r16
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.import imul8x8r16, popa, ptr1:zp
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;---------------------------------------------------------------------------
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; 8x8 => 16 signed multiplication routine.
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.proc _cc65_imul8x8r16
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sta ptr1
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jsr popa
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jmp imul8x8r16
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.endproc
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@ -5,9 +5,7 @@
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;
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;
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.export _cc65_umul8x8r16
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.export _cc65_umul8x8r16
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.import umul8x8r16, popa
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.import umul8x8r16, popa, ptr1:zp
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.include "zeropage.inc"
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;---------------------------------------------------------------------------
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;---------------------------------------------------------------------------
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@ -13,9 +13,9 @@
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;---------------------------------------------------------------------------
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;---------------------------------------------------------------------------
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; 16x16 => 32 signed multiplication routine.
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; 16x16 => 32 signed multiplication routine.
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;
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;
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; lhs rhs result result also in
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; LHS RHS result result also in
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; -------------------------------------------------------------
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; -------------------------------------------------------------
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; ptr1 ax ax:sreg
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; ax ptr1 ax:sreg
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;
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;
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; There is probably a faster way to do this.
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; There is probably a faster way to do this.
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;
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;
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75
libsrc/runtime/imul8x8r16.s
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libsrc/runtime/imul8x8r16.s
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;
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; 2010-11-02, Ullrich von Bassewitz
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; 2014-05-10, Greg King
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;
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; CC65 runtime: 8x8 => 16 signed multiplication
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;
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.export imul8x8r16, imul8x8r16m
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.importzp ptr1, ptr3, tmp1
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.macpack generic
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;---------------------------------------------------------------------------
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; 8x8 => 16 signed multiplication routine.
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;
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; multiplicand multiplier product
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; LHS RHS result
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; -------------------------------------------------------------
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; .A (ptr3-low) ptr1-low .XA
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;
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imul8x8r16:
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sta ptr3
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imul8x8r16m:
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ldx #>0
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bit ptr3
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bpl @L7
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dex
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@L7: stx ptr3+1 ; Extend sign of Left-Hand Side
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ldy #<0 ; Clear .XY accumulator
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ldx #>0
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lda ptr1
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bmi NegMult
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bpl @L2 ; Branch always
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@L0: tya ; Add current multiplicand
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add ptr3
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tay
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txa
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adc ptr3+1
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tax
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@L1: asl ptr3
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rol ptr3+1
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@L2: lsr ptr1 ; Get next bit of Right-Hand Side into carry
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bcs @L0
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bnz @L1 ; Loop if more one-bits in multiplier
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tya ; Put result into cc65's accumulator
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rts
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; The multiplier is negative.
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; Therefore, make it positive; and, subtract when multiplying.
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NegMult:
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eor #%11111111
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sta ptr1
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inc ptr1
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bnz @L2 ; Branch always
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@L0: tya ; Subtract current multiplicand
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sub ptr3
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tay
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txa
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sbc ptr3+1
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tax
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@L1: asl ptr3
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rol ptr3+1
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@L2: lsr ptr1 ; Get next bit of Right-Hand Side into carry
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bcs @L0
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bnz @L1 ; Loop if more one-bits in multiplier
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tya ; Put result into cc65's accumulator
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rts
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@ -13,14 +13,14 @@
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;---------------------------------------------------------------------------
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;---------------------------------------------------------------------------
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; 16x16 => 32 unsigned multiplication routine. Because the overhead for a
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; 16x16 => 32 unsigned multiplication routine. Because the overhead for a
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; 16x16 => 16 unsigned multiplication routine is small, we will tag it with
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; 16x16 => 16 unsigned multiplication routine is small, we will tag it with
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; the matching labels as well.
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; the matching labels, as well.
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;
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;
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; routine lhs rhs result result also in
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; routine LHS RHS result result also in
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; -----------------------------------------------------------------------
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; -----------------------------------------------------------------------
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; umul16x16r32 ptr1 ax ax:sreg ptr1:sreg
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; umul16x16r32 ax ptr1 ax:sreg ptr1:sreg
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; umul16x16r32m ptr1 ptr3 ax:sreg ptr1:sreg
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; umul16x16r32m ptr3 ptr1 ax:sreg ptr1:sreg
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; umul16x16r16 ptr1 ax ax ptr1
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; umul16x16r16 ax ptr1 ax ptr1
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; umul16x16r16m ptr1 ptr3 ax ptr1
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; umul16x16r16m ptr3 ptr1 ax ptr1
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;
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;
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; ptr3 is left intact by the routine.
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; ptr3 is left intact by the routine.
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;
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;
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@ -13,14 +13,14 @@
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;---------------------------------------------------------------------------
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;---------------------------------------------------------------------------
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; 8x16 => 24 unsigned multiplication routine. Because the overhead for a
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; 8x16 => 24 unsigned multiplication routine. Because the overhead for a
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; 8x16 => 16 unsigned multiplication routine is small, we will tag it with
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; 8x16 => 16 unsigned multiplication routine is small, we will tag it with
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; the matching labels as well.
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; the matching labels, as well.
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;
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;
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; routine lhs rhs result result also in
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; routine LHS RHS result result also in
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; -----------------------------------------------------------------------
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; -----------------------------------------------------------------------
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; umul8x16r24 ptr1-lo ax ax:sreg-lo ptr1:sreg-lo
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; umul8x16r24 ax ptr1-low ax:sreg-low ptr1:sreg-low
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; umul8x16r24m ptr1-lo ptr3 ax:sreg-lo ptr1:sreg-lo
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; umul8x16r24m ptr3 ptr1-low ax:sreg-low ptr1:sreg-low
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;
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;
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; ptr3 ist left intact by the routine.
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; ptr3 is left intact by the routine.
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;
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;
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umul8x16r24:
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umul8x16r24:
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@ -1,7 +1,7 @@
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;
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;
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; Ullrich von Bassewitz, 2010-11-02
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; Ullrich von Bassewitz, 2010-11-02
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;
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;
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; CC65 runtime: 8x8 => 16 multiplication
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; CC65 runtime: 8x8 => 16 unsigned multiplication
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;
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;
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.export umul8x8r16, umul8x8r16m
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.export umul8x8r16, umul8x8r16m
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@ -9,11 +9,11 @@
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;---------------------------------------------------------------------------
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;---------------------------------------------------------------------------
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; 8x8 => 16 multiplication routine.
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; 8x8 => 16 unsigned multiplication routine.
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;
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;
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; lhs rhs result result also in
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; LHS RHS result result in also
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; -------------------------------------------------------------
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; -------------------------------------------------------------
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; ptr1-lo ptr3-lo ax ptr1
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; .A (ptr3-low) ptr1-low .XA ptr1
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;
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;
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umul8x8r16:
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umul8x8r16:
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@ -21,7 +21,7 @@ umul8x8r16:
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umul8x8r16m:
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umul8x8r16m:
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lda #0 ; Clear byte 1
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lda #0 ; Clear byte 1
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ldy #8 ; Number of bits
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ldy #8 ; Number of bits
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lsr ptr1 ; Get first bit of lhs into carry
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lsr ptr1 ; Get first bit of RHS into carry
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@L0: bcc @L1
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@L0: bcc @L1
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clc
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clc
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adc ptr3
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adc ptr3
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dey
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dey
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bne @L0
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bne @L0
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tax
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tax
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stx ptr1+1 ; Result in a/x and ptr1
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stx ptr1+1 ; Result in .XA and ptr1
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lda ptr1 ; Load the result
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lda ptr1 ; Load the result
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rts ; Done
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rts ; Done
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