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Added labels for umul16x16r16 and umul16x16r16m.

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git-svn-id: svn://svn.cc65.org/cc65/trunk@5077 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2011-07-10 14:50:18 +00:00
parent bf6b0b9eb7
commit 3812c5c854
1 changed files with 19 additions and 11 deletions
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30
libsrc/runtime/umul16x16r32.s
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@ -5,27 +5,34 @@
;
.export umul16x16r32, umul16x16r32m
.export umul16x16r16, umul16x16r16m
.include "zeropage.inc"
;---------------------------------------------------------------------------
; 16x16 => 32 unsigned multiplication routine.
; 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.
;
; 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
;
; ptr3 is left intact by the routine.
;
umul16x16r32:
umul16x16r16:
sta ptr3
stx ptr3+1
umul16x16r32m:
lda #0
umul16x16r16m:
lda #0
sta sreg+1
ldy #16 ; Number of bits
@ -34,22 +41,23 @@ umul16x16r32m:
@L0: bcc @L1
clc
adc ptr3
adc ptr3
pha
lda ptr3+1
adc sreg+1
sta sreg+1
adc sreg+1
sta sreg+1
pla
@L1: ror sreg+1
ror a
ror ptr1+1
ror ptr1
ror a
ror ptr1+1
ror ptr1
dey
bne @L0
sta sreg ; Save byte 3
lda ptr1 ; Load the result
ldx ptr1+1
rts ; Done
lda ptr1 ; Load the result
ldx ptr1+1
rts ; Done