Tags: X86 CRYPTO ARM MIPS ARM64 ASM L1 .
What does this code do?
PUBLIC _f
; Function compile flags: /Ogtpy
_TEXT SEGMENT
_k0$ = -12 ; size = 4
_k3$ = -8 ; size = 4
_k2$ = -4 ; size = 4
_v$ = 8 ; size = 4
_k1$ = 12 ; size = 4
_k$ = 12 ; size = 4
_f PROC
sub esp, 12 ; 0000000cH
mov ecx, DWORD PTR _v$[esp+8]
mov eax, DWORD PTR [ecx]
mov ecx, DWORD PTR [ecx+4]
push ebx
push esi
mov esi, DWORD PTR _k$[esp+16]
push edi
mov edi, DWORD PTR [esi]
mov DWORD PTR _k0$[esp+24], edi
mov edi, DWORD PTR [esi+4]
mov DWORD PTR _k1$[esp+20], edi
mov edi, DWORD PTR [esi+8]
mov esi, DWORD PTR [esi+12]
xor edx, edx
mov DWORD PTR _k2$[esp+24], edi
mov DWORD PTR _k3$[esp+24], esi
lea edi, DWORD PTR [edx+32]
$LL8@f:
mov esi, ecx
shr esi, 5
add esi, DWORD PTR _k1$[esp+20]
mov ebx, ecx
shl ebx, 4
add ebx, DWORD PTR _k0$[esp+24]
sub edx, 1640531527 ; 61c88647H
xor esi, ebx
lea ebx, DWORD PTR [edx+ecx]
xor esi, ebx
add eax, esi
mov esi, eax
shr esi, 5
add esi, DWORD PTR _k3$[esp+24]
mov ebx, eax
shl ebx, 4
add ebx, DWORD PTR _k2$[esp+24]
xor esi, ebx
lea ebx, DWORD PTR [edx+eax]
xor esi, ebx
add ecx, esi
dec edi
jne SHORT $LL8@f
mov edx, DWORD PTR _v$[esp+20]
pop edi
pop esi
mov DWORD PTR [edx], eax
mov DWORD PTR [edx+4], ecx
pop ebx
add esp, 12 ; 0000000cH
ret 0
_f ENDP
PUSH {r4-r10,lr}
ADD r5,r1,#8
LDM r5,{r5,r7}
LDR r2,[r0,#4]
LDR r3,[r0,#0]
LDR r4,|L0.116|
LDR r6,[r1,#4]
LDR r8,[r1,#0]
MOV r12,#0
MOV r1,r12
|L0.40|
ADD r12,r12,r4
ADD r9,r8,r2,LSL #4
ADD r10,r2,r12
EOR r9,r9,r10
ADD r10,r6,r2,LSR #5
EOR r9,r9,r10
ADD r3,r3,r9
ADD r9,r5,r3,LSL #4
ADD r10,r3,r12
EOR r9,r9,r10
ADD r10,r7,r3,LSR #5
EOR r9,r9,r10
ADD r1,r1,#1
CMP r1,#0x20
ADD r2,r2,r9
STRCS r2,[r0,#4]
STRCS r3,[r0,#0]
BCC |L0.40|
POP {r4-r10,pc}
|L0.116|
DCD 0x9e3779b9
PUSH {r1-r7,lr}
LDR r5,|L0.84|
LDR r3,[r0,#0]
LDR r2,[r0,#4]
STR r5,[sp,#8]
MOVS r6,r1
LDM r6,{r6,r7}
LDR r5,[r1,#8]
STR r6,[sp,#4]
LDR r6,[r1,#0xc]
MOVS r4,#0
MOVS r1,r4
MOV lr,r5
MOV r12,r6
STR r7,[sp,#0]
|L0.30|
LDR r5,[sp,#8]
LSLS r6,r2,#4
ADDS r4,r4,r5
LDR r5,[sp,#4]
LSRS r7,r2,#5
ADDS r5,r6,r5
ADDS r6,r2,r4
EORS r5,r5,r6
LDR r6,[sp,#0]
ADDS r1,r1,#1
ADDS r6,r7,r6
EORS r5,r5,r6
ADDS r3,r5,r3
LSLS r5,r3,#4
ADDS r6,r3,r4
ADD r5,r5,lr
EORS r5,r5,r6
LSRS r6,r3,#5
ADD r6,r6,r12
EORS r5,r5,r6
ADDS r2,r5,r2
CMP r1,#0x20
BCC |L0.30|
STR r3,[r0,#0]
STR r2,[r0,#4]
POP {r1-r7,pc}
|L0.84|
DCD 0x9e3779b9
f:
ldr w3, [x0]
mov w4, 0
ldr w2, [x0,4]
ldr w10, [x1]
ldr w9, [x1,4]
ldr w8, [x1,8]
ldr w7, [x1,12]
.L2:
mov w5, 31161
add w6, w10, w2, lsl 4
movk w5, 0x9e37, lsl 16
add w1, w9, w2, lsr 5
add w4, w4, w5
eor w1, w6, w1
add w5, w2, w4
mov w6, 14112
eor w1, w1, w5
movk w6, 0xc6ef, lsl 16
add w3, w3, w1
cmp w4, w6
add w5, w3, w4
add w6, w8, w3, lsl 4
add w1, w7, w3, lsr 5
eor w1, w6, w1
eor w1, w1, w5
add w2, w2, w1
bne .L2
str w3, [x0]
str w2, [x0,4]
ret
f:
lui $t2, 0x9E37
lui $t1, 0xC6EF
lw $v0, 0($a0)
lw $v1, 4($a0)
lw $t6, 0xC($a1)
lw $t5, 0($a1)
lw $t4, 4($a1)
lw $t3, 8($a1)
li $t2, 0x9E3779B9
li $t1, 0xC6EF3720
move $a1, $zero
loc_2C: # CODE XREF: f+6C
addu $a1, $t2
sll $a2, $v1, 4
addu $t0, $a1, $v1
srl $a3, $v1, 5
addu $a2, $t5
addu $a3, $t4
xor $a2, $t0, $a2
xor $a2, $a3
addu $v0, $a2
sll $a3, $v0, 4
srl $a2, $v0, 5
addu $a3, $t3
addu $a2, $t6
xor $a2, $a3, $a2
addu $a3, $v0, $a1
xor $a2, $a3
bne $a1, $t1, loc_2C
addu $v1, $a2
sw $v1, 4($a0)
jr $ra
sw $v0, 0($a0)
More challenges: challenges.re; about solutions: challenges.re/#Solutions.