Tags: CRYPTO ARM MIPS ARM64 ASM L1 .
This is a well-known cryptographic algorithm from the past. How is it called?
_in$ = 8 ; size = 2
_f PROC
movzx ecx, WORD PTR _in$[esp-4]
lea eax, DWORD PTR [ecx*4]
xor eax, ecx
add eax, eax
xor eax, ecx
shl eax, 2
xor eax, ecx
and eax, 32 ; 00000020H
shl eax, 10 ; 0000000aH
shr ecx, 1
or eax, ecx
ret 0
_f ENDP
f PROC
EOR r1,r0,r0,LSR #2
EOR r1,r1,r0,LSR #3
EOR r1,r1,r0,LSR #5
AND r1,r1,#1
LSR r0,r0,#1
ORR r0,r0,r1,LSL #15
BX lr
ENDP
f PROC
LSRS r1,r0,#2
EORS r1,r1,r0
LSRS r2,r0,#3
EORS r1,r1,r2
LSRS r2,r0,#5
EORS r1,r1,r2
LSLS r1,r1,#31
LSRS r0,r0,#1
LSRS r1,r1,#16
ORRS r0,r0,r1
BX lr
ENDP
f:
uxth w1, w0
lsr w2, w1, 3
lsr w0, w1, 1
eor w2, w2, w1, lsr 2
eor w2, w1, w2
eor w1, w2, w1, lsr 5
and w1, w1, 1
orr w0, w0, w1, lsl 15
ret
f:
andi $a0, 0xFFFF
srl $v1, $a0, 2
srl $v0, $a0, 3
xor $v0, $v1, $v0
xor $v0, $a0, $v0
srl $v1, $a0, 5
xor $v0, $v1
andi $v0, 1
srl $a0, 1
sll $v0, 15
jr $ra
or $v0, $a0
More challenges: challenges.re; about solutions: challenges.re/#Solutions.