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