fix and optimize crypto.asm
also a bit more standardization
This commit is contained in:
Kevin Cathcart
373
crypto.asm
373
crypto.asm
@@ -2,7 +2,7 @@
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; $7F5100 - $7F51FF - Block Cypher Buffer
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!v = "$7F5100"
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!n = "$04"
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!MXResult = "$06"
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!MXResult = "$08" ; an alternate name for the lower 32 bits of dpScratch
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!dpScratch = "$08"
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!keyBase = "$7F50D0"
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@@ -12,168 +12,237 @@
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!sum = "$7F50E8"
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!p = "$7F50EC"
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!rounds = "$05"
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!rounds = "$06"
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!e = "$7F50F0"
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!upperScratch = "$7F50F2"
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CryptoDelta:
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dl #$9e3779b9
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dd #$9e3779b9
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macro LSR32(value,k)
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LDX.w <k>
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?loop:
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LDA <value>+2
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LSR : STA <value>+2 ; do top part
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PHP ; push carry
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LDA <value>
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LSR ; do bottom part
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PLP ; pull carry
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BCC ?nc
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ORA #$80 ; pull in carry
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?nc:
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STA <value>
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DEX
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CPX.w #$0000 : BNE ?loop
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; For use in an unrolled loop
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macro LSR32Single(value)
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CLC;
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LDA.b <value>+2 : ROR : STA.b <value>+2 ; do top part
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LDA.b <value> : ROR : STA.b <value> ; do bottom part
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; ROR handles the carry from the upper byte for us
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endmacro
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macro ASL32(value,k)
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LDX.w <k>
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?loop:
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LDA <value>
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LSR : STA <value> ; do bottom part
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PHP ; push carry
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LDA <value>+2
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LSR
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PLP ; pull carry
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ADC.w #$0000
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STA <value>+2 ; do top part
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DEX
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CPX.w #$0000 : BNE ?loop
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macro ASL32Single(value)
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CLC
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LDA.b <value> : ROL : STA.b <value> ; do bottom part
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LDA.b <value>+2 : ROL : STA.b <value>+2 ; do top part
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; ROL handles the carry from the lower byte for us
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endmacro
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;macro LSR32(value,k)
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; LDX.b <k>
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; ?loop:
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; %LSR32Single(<value>,<k>)
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; DEX : CPX.b #$00 : BNE ?loop
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;endmacro
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;macro ASL32(value,k)
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; LDX.b <k>
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; ?loop:
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; %LSR32Single(<value>,<k>)
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; DEX : CPX.b #$00 : BNE ?loop
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;endmacro
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CryptoMX:
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PHX
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LDA !z : STA !dpScratch
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LDA !z+2 : STA !dpScratch+2
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%LSR32(!dpScratch,#$05)
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LDA !y : STA !dpScratch+4
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LDA !y+2 : STA !dpScratch+6
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%ASL32(!dpScratch+4,#$02)
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LDA !dpScratch : EOR !dpScratch+4 : STA !upperScratch
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LDA !dpScratch+2 : EOR !dpScratch+6 : STA !upperScratch+2
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; upperScratch = (z>>5 ^ y <<2)
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LDA.w !z : STA.b !dpScratch
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LDA.w !z+2 : STA.b !dpScratch+2
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%LSR32Single(!dpScratch)
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%LSR32Single(!dpScratch)
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%LSR32Single(!dpScratch)
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%LSR32Single(!dpScratch)
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%LSR32Single(!dpScratch)
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;%LSR32(!dpScratch,#$05)
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LDA.w !y : STA.b !dpScratch+4
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LDA.w !y+2 : STA.b !dpScratch+6
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%ASL32Single(!dpScratch+4)
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%ASL32Single(!dpScratch+4)
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;%ASL32(!dpScratch+4,#$02)
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LDA.b !dpScratch : EOR.b !dpScratch+4 : STA.w !upperScratch
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LDA.b !dpScratch+2 : EOR.b !dpScratch+6 : STA.w !upperScratch+2
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;================================
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LDA !z : STA !dpScratch
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LDA !z+2 : STA !dpScratch+2
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%ASL32(!dpScratch,#$04)
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LDA !y : STA !dpScratch+4
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LDA !y+2 : STA !dpScratch+6
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%LSR32(!dpScratch,#$03)
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LDA !dpScratch : EOR !dpScratch+4 : STA !upperScratch+4
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LDA !dpScratch+2 : EOR !dpScratch+6 : STA !upperScratch+6
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; upperscratch2 = (y>>3^z<<4)
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LDA.w !z : STA.b !dpScratch
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LDA.w !z+2 : STA.b !dpScratch+2
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%ASL32Single(!dpScratch)
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%ASL32Single(!dpScratch)
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%ASL32Single(!dpScratch)
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%ASL32Single(!dpScratch)
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;%ASL32(!dpScratch,#$04)
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LDA.w !y : STA.b !dpScratch+4
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LDA.w !y+2 : STA.b !dpScratch+6
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%LSR32Single(!dpScratch+4)
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%LSR32Single(!dpScratch+4)
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%LSR32Single(!dpScratch+4)
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;%LSR32(!dpScratch+4,#$03)
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LDA.b !dpScratch : EOR.b !dpScratch+4 : STA.w !upperScratch+4
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LDA.b !dpScratch+2 : EOR.b !dpScratch+6 : STA.w !upperScratch+6
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;================================
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LDA !upperScratch : !ADD !upperScratch+4 : STA !upperScratch
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LDA !upperScratch+2 : ADC !upperScratch+6 : STA !upperScratch+2
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; upperscratch = upperscratch + upperscratch2 ( == (z>>5^y<<2) + (y>>3^z<<4) )
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LDA.w !upperScratch : !ADD.w !upperScratch+4 : STA.w !upperScratch
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LDA.w !upperScratch+2 : ADC.w !upperScratch+6 : STA.w !upperScratch+2
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;================================
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LDA !sum : EOR !y : STA !dpScratch
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LDA !sum+2 : EOR !y+2 : STA !dpScratch+2
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; dpscratch = sum^y
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LDA.w !sum : EOR.w !y : STA.b !dpScratch
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LDA.w !sum+2 : EOR.w !y+2 : STA.b !dpScratch+2
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;================================
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LDA !p : AND.w #$0003 : EOR !e : ASL #2 : TAX ; put (p&3)^e into X
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LDA !keyBase, X : EOR !z : STA !upperScratch+4
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LDA !keyBase+2, X : EOR !z+2 : STA !upperScratch+6
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; dpscratch2 = (k[p&3^e]^z)
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LDA.w !p : AND.w #$0003 : EOR.w !e : ASL #2 : TAX ; put (p&3)^e into X
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LDA.w !keyBase, X : EOR.w !z : STA.b !dpScratch+4
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LDA.w !keyBase+2, X : EOR.w !z+2 : STA.b !dpScratch+6
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;================================
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LDA !upperScratch : EOR !upperScratch+4 : STA !MXResult
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LDA !upperScratch+2 : EOR !upperScratch+6 : STA !MXResult+2
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; upperscratch2 = dpscratch + dpscratch2 (== (sum^y) + (k[p&3^e]^z))
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LDA.b !dpScratch : !ADD.b !dpScratch+4 : STA.w !upperScratch+4
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LDA.b !dpScratch+2 : ADC.b !dpScratch+6 : STA.w !upperScratch+6
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;================================
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; MXResult = uppserscratch ^ upperscratch2
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LDA.w !upperScratch : EOR.w !upperScratch+4 : STA.b !MXResult
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LDA.w !upperScratch+2 : EOR.w !upperScratch+6 : STA.b !MXResult+2
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PLX
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RTS
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!DIVIDEND_LOW = $4204
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!DIVIDEND_HIGH = $4205
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!DIVISOR = $4206
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!QUOTIENT_LOW = $4214
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!QUOTIENT_HIGH = $4215
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;!DIVIDEND_LOW = $4204
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;!DIVIDEND_HIGH = $4205
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;!DIVISOR = $4206
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;!QUOTIENT_LOW = $4214
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;!QUOTIENT_HIGH = $4215
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XXTEA_Decode:
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PHP
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SEP #$20 ; set 8-bit accumulator
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PHP : PHB
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SEP #$30 ; set 8-bit accumulator and index
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LDA.b #$7F : PHA : PLB
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STZ.b !n+1 ; set upper byte of n to be zero, so it can safely be accessed in 16-bit mode
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; search for lookup table index to avoid division and multiplication
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LDX.b #0
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-
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LDA.l .n_lookup, X
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CMP.b !n : !BLT +
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INX
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BRA -
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+
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; rounds = 6 + 52/n;
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LDA.b #52 : STA !DIVIDEND_LOW ; decimal 52
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STZ !DIVIDEND_HIGH
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LDA !n : STA !DIVISOR
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; NOP #8 ; do something useful here?
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LDA.b #$06
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NOP #6
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!ADD !QUOTIENT_LOW
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STA !rounds
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; sum = rounds*DELTA;
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LDA CryptoDelta : STA !dpScratch
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LDA CryptoDelta+1 : STA !dpScratch+1
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LDA CryptoDelta+2 : STA !dpScratch+2
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LDA CryptoDelta+3 : STA !dpScratch+3
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JSR .multiply
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LDA !dpScratch
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STA !sum
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; y = v[0];
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LDA.l .round_counts, X : STA.b !rounds : STZ.b !rounds+1
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REP #$20 ; set 16-bit accumulator
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LDA !v : STA !y
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LDA !v+2 : STA !y+2
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; sum = rounds*DELTA;
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TXA : ASL #2 : TAX
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LDA.l .initial_sums, X : STA.w !sum
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LDA.l .initial_sums+2, X : STA.w !sum+2
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; y = v[0];
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LDA.w !v : STA.w !y
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LDA.w !v+2 : STA.w !y+2
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---
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LDA !sum : LSR #2 : AND #$03 : STA !e ; e = (sum >> 2) & 3;
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LDA !n : !SUB #$01 : STA !p ; for (p=n-1; p>0; p--) {
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--
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LDA.w !sum : LSR #2 : AND.w #$0003 : STA.w !e ; e = (sum >> 2) & 3;
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LDA.b !n : DEC : STA.w !p
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-- BEQ + ; for (p=n-1; p>0; p--) {
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; z = v[p-1];
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DEC : ASL #2 : TAX
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LDA !v, X : STA !z
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LDA !v+2, X : STA !z+2
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ASL #2 : TAX
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LDA.w !v-4, X : STA.w !z
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LDA.w !v-4+2, X : STA.w !z+2
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; y = v[p] -= MX;
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JSR CryptoMX
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LDA !p : ASL #2 : TAX
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LDA !v, X : !SUB !MXResult : STA !v, X : STA !y
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LDA !v+2, X : SBC !MXResult+2 : STA !v+2, X : STA !y+2
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LDA !p : DEC : STA !p : BNE -- ; }
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LDA.w !p : ASL #2 : TAX
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LDA.w !v, X : !SUB.b !MXResult : STA.w !v, X : STA.w !y
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LDA.w !v+2, X : SBC.b !MXResult+2 : STA.w !v+2, X : STA.w !y+2
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LDA.w !p : DEC : STA.w !p : BRA -- ; }
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+
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; z = v[n-1];
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LDA !n : DEC : ASL #2 : TAX
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LDA !v, X : STA !z
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LDA !v+2, X : STA !z+2
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LDA.b !n : DEC : ASL #2 : TAX
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LDA.w !v, X : STA.w !z
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LDA.w !v+2, X : STA.w !z+2
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; y = v[0] -= MX;
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JSR CryptoMX
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LDA !v : !SUB !MXResult : STA !v : STA !y
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LDA !v+2 : SBC !MXResult+2 : STA !v+2 : STA !y+2
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LDA.w !v : !SUB.b !MXResult : STA.w !v : STA.w !y
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LDA.w !v+2 : SBC.b !MXResult+2 : STA.w !v+2 : STA.w !y+2
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; sum -= DELTA;
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LDA !sum : !SUB CryptoDelta : STA !sum
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LDA !sum+2 : !SUB CryptoDelta+2 : STA !sum+2
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LDA !rounds : BEQ + : BRL --- : + ; } while (--rounds);
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PLP
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LDA.w !sum : !SUB.l CryptoDelta : STA.w !sum
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LDA.w !sum+2 : SBC.l CryptoDelta+2 : STA.w !sum+2
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DEC !rounds : BEQ + : BRL --- : + ; } while (--rounds);
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PLB : PLP
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RTL
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; Note: uncomment any values from these tables that correspond to values of n actually in use
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; (unused values are commented out to improve performance/ avoid wasting space)
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.n_lookup
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;db 52 ; n > 52
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;db 26 ; n is 27 to 52
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;db 17 ; n is 18 to 26
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;db 13 ; n is 14 to 17
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;db 10 ; n is 11 to 13
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;db 8 ; n is 9 to 10
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;db 7 ; n is 8
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;db 6 ; n is 7
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;db 5 ; n is 6
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;db 4 ; n is 5
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;db 3 ; n is 4
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;db 2 ; n is 3
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db 1 ; n is 2
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.round_counts
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;db 6 ; n > 52
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;db 7 ; n is 27 to 52
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;db 8 ; n is 18 to 26
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;db 9 ; n is 14 to 17
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;db 10 ; n is 11 to 13
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;db 11 ; n is 9 to 10
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;db 12 ; n is 8
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;db 13 ; n is 7
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;db 14 ; n is 6
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;db 16 ; n is 5
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;db 19 ; n is 4
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;db 23 ; n is 3
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db 32 ; n is 2
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.initial_sums
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;dd 6*$9e3779b9 ; n > 52
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;dd 7*$9e3779b9 ; n is 27 to 52
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;dd 8*$9e3779b9 ; n is 18 to 26
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;dd 9*$9e3779b9 ; n is 14 to 17
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;dd 10*$9e3779b9 ; n is 11 to 13
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;dd 11*$9e3779b9 ; n is 9 to 10
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;dd 12*$9e3779b9 ; n is 8
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;dd 13*$9e3779b9 ; n is 7
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;dd 14*$9e3779b9 ; n is 6
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;dd 16*$9e3779b9 ; n is 5
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;dd 19*$9e3779b9 ; n is 4
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;dd 23*$9e3779b9 ; n is 3
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dd 32*$9e3779b9 ; n is 2
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;void btea(uint32_t *v, int n, uint32_t const key[4]) {
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; uint32_t y, z, sum;
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; unsigned p, rounds, e;
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@@ -195,47 +264,6 @@ RTL
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; } while (--rounds);
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; }
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.multiply
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LDA #$00
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STA !upperScratch+4 ;Clear upper half of
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STA !upperScratch+5 ;!upperScratchuct
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STA !upperScratch+6
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STA !upperScratch+7
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LDX #$20 ;Set binary count to 32
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.shift_r
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LSR !dpScratch+3 ;Shift multiplyer right
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ROR !dpScratch+2
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ROR !dpScratch+1
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ROR !dpScratch
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BCC .rotate_r ;Go rotate right if c = 0
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LDA !upperScratch+4 ;Get upper half of !upperScratchuct
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!ADD !rounds ; and add multiplicand to it
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STA !upperScratch+4
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LDA !upperScratch+5
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ADC.w #$00
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STA !upperScratch+5
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LDA !upperScratch+6
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ADC.w #$00
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STA !upperScratch+6
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LDA !upperScratch+7
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ADC.w #$00
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.rotate_r
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ROR a ;Rotate partial !upperScratchuct
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STA !upperScratch+7 ; right
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ROR !upperScratch+6
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ROR !upperScratch+5
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ROR !upperScratch+4
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ROR !upperScratch+3
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ROR !upperScratch+2
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ROR !upperScratch+1
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ROR !upperScratch
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DEX ;Decrement bit count and
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BNE .shift_r ; loop until 32 bits are done
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;LDA MULXP1 ;Add dps and put sum in MULXP2
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;!ADD MULXP2
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;STA MULXP2
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RTS
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;BTEA will encode or decode n words as a single block where n > 1
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;
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;v is the n word data vector
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@@ -245,7 +273,6 @@ RTS
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;assumes 32 bit 'long' and same endian coding and decoding
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;#include <stdint.h>
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;#define DELTA 0x9e3779b9
|
||||
;#define MX (((z>>5^y<<2) + (y>>3^z<<4)) ^ ((sum^y) + (key[(p&3)^e] ^ z)))
|
||||
;#define MX ((((z>>5)^(y<<2)) + ((y>>3)^(z<<4))) ^ ((sum^y) + (key[(p&3)^e] ^ z)))
|
||||
;
|
||||
;void btea(uint32_t *v, int n, uint32_t const key[4]) {
|
||||
@@ -259,7 +286,7 @@ RTS
|
||||
; sum += DELTA;
|
||||
; e = (sum >> 2) & 3;
|
||||
; for (p=0; p<n-1; p++) {
|
||||
; y = v[p+1];
|
||||
; y = v[p+1];
|
||||
; z = v[p] += MX;
|
||||
; }
|
||||
; y = v[0];
|
||||
@@ -281,4 +308,4 @@ RTS
|
||||
; sum -= DELTA;
|
||||
; } while (--rounds);
|
||||
; }
|
||||
;}
|
||||
;}
|
||||
|
||||
Reference in New Issue
Block a user