diff options
Diffstat (limited to 'crypto/ec/asm/ecp_nistz256-armv4.pl')
| -rwxr-xr-x | crypto/ec/asm/ecp_nistz256-armv4.pl | 124 |
1 files changed, 74 insertions, 50 deletions
diff --git a/crypto/ec/asm/ecp_nistz256-armv4.pl b/crypto/ec/asm/ecp_nistz256-armv4.pl index 73b7a55806..de3cd5cd0f 100755 --- a/crypto/ec/asm/ecp_nistz256-armv4.pl +++ b/crypto/ec/asm/ecp_nistz256-armv4.pl @@ -174,10 +174,7 @@ __ecp_nistz256_mul_by_2: adcs $a6,$a6,$a6 mov $ff,#0 adcs $a7,$a7,$a7 -#ifdef __thumb2__ - it cs -#endif - movcs $ff,#-1 @ $ff = carry ? -1 : 0 + adc $ff,$ff,#0 b .Lreduce_by_sub .size __ecp_nistz256_mul_by_2,.-__ecp_nistz256_mul_by_2 @@ -228,35 +225,45 @@ __ecp_nistz256_add: adcs $a6,$a6,$t2 mov $ff,#0 adcs $a7,$a7,$t3 -#ifdef __thumb2__ - it cs -#endif - movcs $ff,#-1 @ $ff = carry ? -1 : 0, "broadcast" carry + adc $ff,$ff,#0 ldr lr,[sp],#4 @ pop lr .Lreduce_by_sub: - @ if a+b carries, subtract modulus. + @ if a+b >= modulus, subtract modulus. @ + @ But since comparison implies subtraction, we subtract + @ modulus and then add it back if subraction borrowed. + + subs $a0,$a0,#-1 + sbcs $a1,$a1,#-1 + sbcs $a2,$a2,#-1 + sbcs $a3,$a3,#0 + sbcs $a4,$a4,#0 + sbcs $a5,$a5,#0 + sbcs $a6,$a6,#1 + sbcs $a7,$a7,#-1 + sbc $ff,$ff,#0 + @ Note that because mod has special form, i.e. consists of @ 0xffffffff, 1 and 0s, we can conditionally synthesize it by - @ using value of broadcasted carry as a whole or extracting - @ single bit. Follow $ff register... + @ using value of borrow as a whole or extracting single bit. + @ Follow $ff register... - subs $a0,$a0,$ff @ subtract synthesized modulus - sbcs $a1,$a1,$ff + adds $a0,$a0,$ff @ add synthesized modulus + adcs $a1,$a1,$ff str $a0,[$r_ptr,#0] - sbcs $a2,$a2,$ff + adcs $a2,$a2,$ff str $a1,[$r_ptr,#4] - sbcs $a3,$a3,#0 + adcs $a3,$a3,#0 str $a2,[$r_ptr,#8] - sbcs $a4,$a4,#0 + adcs $a4,$a4,#0 str $a3,[$r_ptr,#12] - sbcs $a5,$a5,#0 + adcs $a5,$a5,#0 str $a4,[$r_ptr,#16] - sbcs $a6,$a6,$ff,lsr#31 + adcs $a6,$a6,$ff,lsr#31 str $a5,[$r_ptr,#20] - sbcs $a7,$a7,$ff + adcs $a7,$a7,$ff str $a6,[$r_ptr,#24] str $a7,[$r_ptr,#28] @@ -304,26 +311,29 @@ __ecp_nistz256_mul_by_3: adcs $a6,$a6,$a6 mov $ff,#0 adcs $a7,$a7,$a7 -#ifdef __thumb2__ - it cs -#endif - movcs $ff,#-1 @ $ff = carry ? -1 : 0, "broadcast" carry - - subs $a0,$a0,$ff @ subtract synthesized modulus, see - @ .Lreduce_by_sub for details, except - @ that we don't write anything to - @ memory, but keep intermediate - @ results in registers... - sbcs $a1,$a1,$ff - sbcs $a2,$a2,$ff + adc $ff,$ff,#0 + + subs $a0,$a0,#-1 @ .Lreduce_by_sub but without stores + sbcs $a1,$a1,#-1 + sbcs $a2,$a2,#-1 sbcs $a3,$a3,#0 sbcs $a4,$a4,#0 - ldr $b_ptr,[$a_ptr,#0] sbcs $a5,$a5,#0 + sbcs $a6,$a6,#1 + sbcs $a7,$a7,#-1 + sbc $ff,$ff,#0 + + adds $a0,$a0,$ff @ add synthesized modulus + adcs $a1,$a1,$ff + adcs $a2,$a2,$ff + adcs $a3,$a3,#0 + adcs $a4,$a4,#0 + ldr $b_ptr,[$a_ptr,#0] + adcs $a5,$a5,#0 ldr $t1,[$a_ptr,#4] - sbcs $a6,$a6,$ff,lsr#31 + adcs $a6,$a6,$ff,lsr#31 ldr $t2,[$a_ptr,#8] - sbcs $a7,$a7,$ff + adc $a7,$a7,$ff ldr $t0,[$a_ptr,#12] adds $a0,$a0,$b_ptr @ 2*a[0:7]+=a[0:7] @@ -339,10 +349,7 @@ __ecp_nistz256_mul_by_3: adcs $a6,$a6,$t2 mov $ff,#0 adcs $a7,$a7,$t3 -#ifdef __thumb2__ - it cs -#endif - movcs $ff,#-1 @ $ff = carry ? -1 : 0, "broadcast" carry + adc $ff,$ff,#0 ldr lr,[sp],#4 @ pop lr b .Lreduce_by_sub @@ -1210,25 +1217,42 @@ __ecp_nistz256_add_self: adcs $a6,$a6,$a6 mov $ff,#0 adcs $a7,$a7,$a7 -#ifdef __thumb2__ - it cs -#endif - movcs $ff,#-1 @ $ff = carry ? -1 : 0 + adc $ff,$ff,#0 + + @ if a+b >= modulus, subtract modulus. + @ + @ But since comparison implies subtraction, we subtract + @ modulus and then add it back if subraction borrowed. + + subs $a0,$a0,#-1 + sbcs $a1,$a1,#-1 + sbcs $a2,$a2,#-1 + sbcs $a3,$a3,#0 + sbcs $a4,$a4,#0 + sbcs $a5,$a5,#0 + sbcs $a6,$a6,#1 + sbcs $a7,$a7,#-1 + sbc $ff,$ff,#0 - subs $a0,$a0,$ff @ subtract synthesized modulus - sbcs $a1,$a1,$ff + @ Note that because mod has special form, i.e. consists of + @ 0xffffffff, 1 and 0s, we can conditionally synthesize it by + @ using value of borrow as a whole or extracting single bit. + @ Follow $ff register... + + adds $a0,$a0,$ff @ add synthesized modulus + adcs $a1,$a1,$ff str $a0,[$r_ptr,#0] - sbcs $a2,$a2,$ff + adcs $a2,$a2,$ff str $a1,[$r_ptr,#4] - sbcs $a3,$a3,#0 + adcs $a3,$a3,#0 str $a2,[$r_ptr,#8] - sbcs $a4,$a4,#0 + adcs $a4,$a4,#0 str $a3,[$r_ptr,#12] - sbcs $a5,$a5,#0 + adcs $a5,$a5,#0 str $a4,[$r_ptr,#16] - sbcs $a6,$a6,$ff,lsr#31 + adcs $a6,$a6,$ff,lsr#31 str $a5,[$r_ptr,#20] - sbcs $a7,$a7,$ff + adcs $a7,$a7,$ff str $a6,[$r_ptr,#24] str $a7,[$r_ptr,#28] |