146 lines
3.2 KiB
ArmAsm
146 lines
3.2 KiB
ArmAsm
.text
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.global bn_mul_mont
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.type bn_mul_mont,%function
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.align 2
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bn_mul_mont:
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stmdb sp!,{r0,r2} @ sp points at argument block
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ldr r0,[sp,#3*4] @ load num
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cmp r0,#2
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movlt r0,#0
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addlt sp,sp,#2*4
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blt .Labrt
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stmdb sp!,{r4-r12,lr} @ save 10 registers
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mov r0,r0,lsl#2 @ rescale r0 for byte count
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sub sp,sp,r0 @ alloca(4*num)
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sub sp,sp,#4 @ +extra dword
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sub r0,r0,#4 @ "num=num-1"
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add r4,r2,r0 @ &bp[num-1]
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add r0,sp,r0 @ r0 to point at &tp[num-1]
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ldr r8,[r0,#14*4] @ &n0
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ldr r2,[r2] @ bp[0]
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ldr r5,[r1],#4 @ ap[0],ap++
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ldr r6,[r3],#4 @ np[0],np++
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ldr r8,[r8] @ *n0
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str r4,[r0,#15*4] @ save &bp[num]
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umull r10,r11,r5,r2 @ ap[0]*bp[0]
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str r8,[r0,#14*4] @ save n0 value
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mul r8,r10,r8 @ "tp[0]"*n0
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mov r12,#0
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umlal r10,r12,r6,r8 @ np[0]*n0+"t[0]"
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mov r4,sp
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.L1st:
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ldr r5,[r1],#4 @ ap[j],ap++
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mov r10,r11
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mov r11,#0
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umlal r10,r11,r5,r2 @ ap[j]*bp[0]
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ldr r6,[r3],#4 @ np[j],np++
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mov r14,#0
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umlal r12,r14,r6,r8 @ np[j]*n0
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adds r12,r12,r10
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str r12,[r4],#4 @ tp[j-1]=,tp++
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adc r12,r14,#0
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cmp r4,r0
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bne .L1st
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adds r12,r12,r11
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mov r14,#0
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adc r14,r14,#0
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ldr r4,[r0,#13*4] @ restore bp
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str r12,[r0] @ tp[num-1]=
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ldr r8,[r0,#14*4] @ restore n0
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str r14,[r0,#4] @ tp[num]=
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.Louter:
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sub r7,r0,sp @ "original" r0-1 value
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sub r1,r1,r7 @ "rewind" ap to &ap[1]
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sub r3,r3,r7 @ "rewind" np to &np[1]
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ldr r2,[r4,#4]! @ *(++bp)
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ldr r5,[r1,#-4] @ ap[0]
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ldr r6,[r3,#-4] @ np[0]
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ldr r10,[sp] @ tp[0]
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ldr r7,[sp,#4] @ tp[1]
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mov r11,#0
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umlal r10,r11,r5,r2 @ ap[0]*bp[i]+tp[0]
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str r4,[r0,#13*4] @ save bp
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mul r8,r10,r8
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mov r12,#0
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umlal r10,r12,r6,r8 @ np[0]*n0+"tp[0]"
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mov r4,sp
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.Linner:
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ldr r5,[r1],#4 @ ap[j],ap++
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adds r10,r11,r7 @ +=tp[j]
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mov r11,#0
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umlal r10,r11,r5,r2 @ ap[j]*bp[i]
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ldr r6,[r3],#4 @ np[j],np++
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mov r14,#0
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umlal r12,r14,r6,r8 @ np[j]*n0
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ldr r7,[r4,#8] @ tp[j+1]
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adc r11,r11,#0
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adds r12,r12,r10
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str r12,[r4],#4 @ tp[j-1]=,tp++
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adc r12,r14,#0
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cmp r4,r0
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bne .Linner
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adds r12,r12,r11
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mov r14,#0
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adc r14,r14,#0
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adds r12,r12,r7
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adc r14,r14,#0
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ldr r4,[r0,#13*4] @ restore bp
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ldr r7,[r0,#15*4] @ restore &bp[num]
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str r12,[r0] @ tp[num-1]=
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ldr r8,[r0,#14*4] @ restore n0
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str r14,[r0,#4] @ tp[num]=
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cmp r4,r7
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bne .Louter
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ldr r2,[r0,#12*4] @ pull rp
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add r0,r0,#4 @ r0 to point at &tp[num]
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sub r5,r0,sp @ "original" num value
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mov r4,sp @ "rewind" r4
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mov r1,r4 @ "borrow" r1
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sub r3,r3,r5 @ "rewind" r3 to &np[0]
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subs r7,r7,r7 @ "clear" carry flag
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.Lsub: ldr r7,[r4],#4
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ldr r6,[r3],#4
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sbcs r7,r7,r6 @ tp[j]-np[j]
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str r7,[r2],#4 @ rp[j]=
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teq r4,r0 @ preserve carry
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bne .Lsub
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sbcs r14,r14,#0 @ upmost carry
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mov r4,sp @ "rewind" r4
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sub r2,r2,r5 @ "rewind" r2
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and r1,r4,r14
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bic r3,r2,r14
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orr r1,r1,r3 @ ap=borrow?tp:rp
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.Lcopy: ldr r7,[r1],#4 @ copy or in-place refresh
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str sp,[r4],#4 @ zap tp
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str r7,[r2],#4
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cmp r4,r0
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bne .Lcopy
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add sp,r0,#4 @ skip over tp[num+1]
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ldmia sp!,{r4-r12,lr} @ restore registers
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add sp,sp,#2*4 @ skip over {r0,r2}
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mov r0,#1
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.Labrt: tst lr,#1
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moveq pc,lr @ be binary compatible with V4, yet
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.word 0xe12fff1e @ interoperable with Thumb ISA:-)
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.size bn_mul_mont,.-bn_mul_mont
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.asciz "Montgomery multiplication for ARMv4, CRYPTOGAMS by <appro@openssl.org>"
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.align 2
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