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65816-crypto
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Optimize the operations used for various shift sizes in MD5.

This commit is contained in:
Stephen Heumann 2017-07-04 13:57:01 -05:00
parent 748e0b5c24
commit 1d1d5251f6
2 changed files with 107 additions and 2 deletions
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2
md5.asm
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@ -26,7 +26,7 @@ a_ gequ 12 ; elements of state
b gequ 16
c gequ 20
d gequ 24
;unused gequ 28
temp2 gequ 28
;unused gequ 32
temp gequ 36
h0 gequ 40

107
md5.macros
View File

@ -32,6 +32,24 @@
.end
mend
* Expects the contents of &loc+2 to be loaded in A already
macro
ROTR4CONT &loc,&n
aif &n>16,.dorotl
lcla &i
&i seta &n
.rotrloop
lsr a ;to set carry
ror &loc
ror &loc+2
&i seta &i-1
aif &i>0,.rotrloop
ago .end
.dorotl
ROTL4 &loc,32-&n
.end
mend
* Left-rotate 32-bit value in &loc (DP or 16-bit address) by &n positions
macro
ROTL4 &loc,&n
@ -51,6 +69,24 @@
.end2
mend
* Expects the contents of &loc to be loaded in A already
macro
ROTL4CONT &loc,&n
aif &n>16,.dorotr2
lcla &i
&i seta &n
.rotlloop2
asl a ;to set carry
rol &loc+2
rol &loc
&i seta &i-1
aif &i>0,.rotlloop2
ago .end2
.dorotr2
ROTR4 &loc,32-&n
.end2
mend
* &to := &from ROTR4 &n
macro
ROTR4MOVE &to,&from,&n
@ -95,6 +131,75 @@
.end4
mend
* Left-rotate with various optimizations applied
macro
ROTL4AUTO &loc,&n
aif &n>5,.skip1
ROTL4 &loc,&n
mexit
.skip1
aif &n>7,.skip2
ldx &loc+1
lda &loc+3
and #$00FF
sta temp2
lda &loc-1
and #$FF00
ora temp2
sta &loc
stx &loc+2
txa
ROTR4CONT &loc,8-&n
mexit
.skip2
aif &n>11,.skip3
ldx &loc+1
lda &loc+3
and #$00FF
sta temp2
lda &loc-1
and #$FF00
ora temp2
sta &loc
stx &loc+2
ROTL4CONT &loc,&n-8
mexit
.skip3
aif &n>15,.skip4
lda &loc
ldy &loc+2
sta &loc+2
sty &loc
ROTR4CONT &loc,16-&n
mexit
.skip4
aif &n>16,.skip5
lda &loc
ldy &loc+2
sta &loc+2
sty &loc
mexit
.skip5
aif &n>21,.skip6
lda &loc+2
ldy &loc
sta &loc
sty &loc+2
ROTL4CONT &loc,&n-16
mexit
.skip6
ldx &loc+1
lda &loc+3
and #$00FF
sta temp2
lda &loc-1
and #$FF00
ora temp2
sta &loc+2
stx &loc
ROTR4CONT &loc,24-&n
mend
* This makes a function wrapper that is callable from C,
* taking a pointer to the context structure as its argument.
@ -219,7 +324,7 @@
iny
sty idx
ROTL4 temp,&shift
ROTL4AUTO temp,&shift
clc
lda &b