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v2fly/external/github.com/cloudflare/sidh/p503/arith_arm64.s
2019-01-17 15:33:18 +01:00

803 lines
15 KiB
ArmAsm

// +build arm64,!noasm
#include "textflag.h"
TEXT ·fp503ConditionalSwap(SB), NOSPLIT, $0-17
MOVD x+0(FP), R0
MOVD y+8(FP), R1
MOVB choice+16(FP), R2
// Set flags
// If choice is not 0 or 1, this implementation will swap completely
CMP $0, R2
LDP 0(R0), (R3, R4)
LDP 0(R1), (R5, R6)
CSEL EQ, R3, R5, R7
CSEL EQ, R4, R6, R8
STP (R7, R8), 0(R0)
CSEL NE, R3, R5, R9
CSEL NE, R4, R6, R10
STP (R9, R10), 0(R1)
LDP 16(R0), (R3, R4)
LDP 16(R1), (R5, R6)
CSEL EQ, R3, R5, R7
CSEL EQ, R4, R6, R8
STP (R7, R8), 16(R0)
CSEL NE, R3, R5, R9
CSEL NE, R4, R6, R10
STP (R9, R10), 16(R1)
LDP 32(R0), (R3, R4)
LDP 32(R1), (R5, R6)
CSEL EQ, R3, R5, R7
CSEL EQ, R4, R6, R8
STP (R7, R8), 32(R0)
CSEL NE, R3, R5, R9
CSEL NE, R4, R6, R10
STP (R9, R10), 32(R1)
LDP 48(R0), (R3, R4)
LDP 48(R1), (R5, R6)
CSEL EQ, R3, R5, R7
CSEL EQ, R4, R6, R8
STP (R7, R8), 48(R0)
CSEL NE, R3, R5, R9
CSEL NE, R4, R6, R10
STP (R9, R10), 48(R1)
RET
TEXT ·fp503AddReduced(SB), NOSPLIT, $0-24
MOVD z+0(FP), R2
MOVD x+8(FP), R0
MOVD y+16(FP), R1
// Load first summand into R3-R10
// Add first summand and second summand and store result in R3-R10
LDP 0(R0), (R3, R4)
LDP 0(R1), (R11, R12)
LDP 16(R0), (R5, R6)
LDP 16(R1), (R13, R14)
ADDS R11, R3
ADCS R12, R4
ADCS R13, R5
ADCS R14, R6
LDP 32(R0), (R7, R8)
LDP 32(R1), (R11, R12)
LDP 48(R0), (R9, R10)
LDP 48(R1), (R13, R14)
ADCS R11, R7
ADCS R12, R8
ADCS R13, R9
ADC R14, R10
// Subtract 2 * p503 in R11-R17 from the result in R3-R10
LDP ·p503x2+0(SB), (R11, R12)
LDP ·p503x2+24(SB), (R13, R14)
SUBS R11, R3
SBCS R12, R4
LDP ·p503x2+40(SB), (R15, R16)
SBCS R12, R5
SBCS R13, R6
MOVD ·p503x2+56(SB), R17
SBCS R14, R7
SBCS R15, R8
SBCS R16, R9
SBCS R17, R10
SBC ZR, ZR, R19
// If x + y - 2 * p503 < 0, R19 is 1 and 2 * p503 should be added
AND R19, R11
AND R19, R12
AND R19, R13
AND R19, R14
AND R19, R15
AND R19, R16
AND R19, R17
ADDS R11, R3
ADCS R12, R4
STP (R3, R4), 0(R2)
ADCS R12, R5
ADCS R13, R6
STP (R5, R6), 16(R2)
ADCS R14, R7
ADCS R15, R8
STP (R7, R8), 32(R2)
ADCS R16, R9
ADC R17, R10
STP (R9, R10), 48(R2)
RET
TEXT ·fp503SubReduced(SB), NOSPLIT, $0-24
MOVD z+0(FP), R2
MOVD x+8(FP), R0
MOVD y+16(FP), R1
// Load x into R3-R10
// Subtract y from x and store result in R3-R10
LDP 0(R0), (R3, R4)
LDP 0(R1), (R11, R12)
LDP 16(R0), (R5, R6)
LDP 16(R1), (R13, R14)
SUBS R11, R3
SBCS R12, R4
SBCS R13, R5
SBCS R14, R6
LDP 32(R0), (R7, R8)
LDP 32(R1), (R11, R12)
LDP 48(R0), (R9, R10)
LDP 48(R1), (R13, R14)
SBCS R11, R7
SBCS R12, R8
SBCS R13, R9
SBCS R14, R10
SBC ZR, ZR, R19
// If x - y < 0, R19 is 1 and 2 * p503 should be added
LDP ·p503x2+0(SB), (R11, R12)
LDP ·p503x2+24(SB), (R13, R14)
AND R19, R11
AND R19, R12
LDP ·p503x2+40(SB), (R15, R16)
AND R19, R13
AND R19, R14
MOVD ·p503x2+56(SB), R17
AND R19, R15
AND R19, R16
AND R19, R17
ADDS R11, R3
ADCS R12, R4
STP (R3, R4), 0(R2)
ADCS R12, R5
ADCS R13, R6
STP (R5, R6), 16(R2)
ADCS R14, R7
ADCS R15, R8
STP (R7, R8), 32(R2)
ADCS R16, R9
ADC R17, R10
STP (R9, R10), 48(R2)
RET
TEXT ·fp503AddLazy(SB), NOSPLIT, $0-24
MOVD z+0(FP), R2
MOVD x+8(FP), R0
MOVD y+16(FP), R1
// Load first summand into R3-R10
// Add first summand and second summand and store result in R3-R10
LDP 0(R0), (R3, R4)
LDP 0(R1), (R11, R12)
LDP 16(R0), (R5, R6)
LDP 16(R1), (R13, R14)
ADDS R11, R3
ADCS R12, R4
STP (R3, R4), 0(R2)
ADCS R13, R5
ADCS R14, R6
STP (R5, R6), 16(R2)
LDP 32(R0), (R7, R8)
LDP 32(R1), (R11, R12)
LDP 48(R0), (R9, R10)
LDP 48(R1), (R13, R14)
ADCS R11, R7
ADCS R12, R8
STP (R7, R8), 32(R2)
ADCS R13, R9
ADC R14, R10
STP (R9, R10), 48(R2)
RET
TEXT ·fp503X2AddLazy(SB), NOSPLIT, $0-24
MOVD z+0(FP), R2
MOVD x+8(FP), R0
MOVD y+16(FP), R1
LDP 0(R0), (R3, R4)
LDP 0(R1), (R11, R12)
LDP 16(R0), (R5, R6)
LDP 16(R1), (R13, R14)
ADDS R11, R3
ADCS R12, R4
STP (R3, R4), 0(R2)
ADCS R13, R5
ADCS R14, R6
STP (R5, R6), 16(R2)
LDP 32(R0), (R7, R8)
LDP 32(R1), (R11, R12)
LDP 48(R0), (R9, R10)
LDP 48(R1), (R13, R14)
ADCS R11, R7
ADCS R12, R8
STP (R7, R8), 32(R2)
ADCS R13, R9
ADCS R14, R10
STP (R9, R10), 48(R2)
LDP 64(R0), (R3, R4)
LDP 64(R1), (R11, R12)
LDP 80(R0), (R5, R6)
LDP 80(R1), (R13, R14)
ADCS R11, R3
ADCS R12, R4
STP (R3, R4), 64(R2)
ADCS R13, R5
ADCS R14, R6
STP (R5, R6), 80(R2)
LDP 96(R0), (R7, R8)
LDP 96(R1), (R11, R12)
LDP 112(R0), (R9, R10)
LDP 112(R1), (R13, R14)
ADCS R11, R7
ADCS R12, R8
STP (R7, R8), 96(R2)
ADCS R13, R9
ADC R14, R10
STP (R9, R10), 112(R2)
RET
TEXT ·fp503X2SubLazy(SB), NOSPLIT, $0-24
MOVD z+0(FP), R2
MOVD x+8(FP), R0
MOVD y+16(FP), R1
LDP 0(R0), (R3, R4)
LDP 0(R1), (R11, R12)
LDP 16(R0), (R5, R6)
LDP 16(R1), (R13, R14)
SUBS R11, R3
SBCS R12, R4
STP (R3, R4), 0(R2)
SBCS R13, R5
SBCS R14, R6
STP (R5, R6), 16(R2)
LDP 32(R0), (R7, R8)
LDP 32(R1), (R11, R12)
LDP 48(R0), (R9, R10)
LDP 48(R1), (R13, R14)
SBCS R11, R7
SBCS R12, R8
STP (R7, R8), 32(R2)
SBCS R13, R9
SBCS R14, R10
STP (R9, R10), 48(R2)
LDP 64(R0), (R3, R4)
LDP 64(R1), (R11, R12)
LDP 80(R0), (R5, R6)
LDP 80(R1), (R13, R14)
SBCS R11, R3
SBCS R12, R4
SBCS R13, R5
SBCS R14, R6
LDP 96(R0), (R7, R8)
LDP 96(R1), (R11, R12)
LDP 112(R0), (R9, R10)
LDP 112(R1), (R13, R14)
SBCS R11, R7
SBCS R12, R8
SBCS R13, R9
SBCS R14, R10
SBC ZR, ZR, R15
// If x - y < 0, R15 is 1 and p503 should be added
LDP ·p503+16(SB), (R16, R17)
LDP ·p503+32(SB), (R19, R20)
AND R15, R16
AND R15, R17
LDP ·p503+48(SB), (R21, R22)
AND R15, R19
AND R15, R20
AND R15, R21
AND R15, R22
ADDS R16, R3
ADCS R16, R4
STP (R3, R4), 64(R2)
ADCS R16, R5
ADCS R17, R6
STP (R5, R6), 80(R2)
ADCS R19, R7
ADCS R20, R8
STP (R7, R8), 96(R2)
ADCS R21, R9
ADC R22, R10
STP (R9, R10), 112(R2)
RET
// Expects that X0*Y0 is already in Z0(low),Z3(high) and X0*Y1 in Z1(low),Z2(high)
// Z0 is not actually touched
// Result of (X0-X1) * (Y0-Y1) will be in Z0-Z3
// Inputs get overwritten, except for X1
#define mul128x128comba(X0, X1, Y0, Y1, Z0, Z1, Z2, Z3, T0) \
MUL X1, Y0, X0 \
UMULH X1, Y0, Y0 \
ADDS Z3, Z1 \
ADC ZR, Z2 \
\
MUL Y1, X1, T0 \
UMULH Y1, X1, Y1 \
ADDS X0, Z1 \
ADCS Y0, Z2 \
ADC ZR, ZR, Z3 \
\
ADDS T0, Z2 \
ADC Y1, Z3
// Expects that X points to (X0-X1)
// Result of (X0-X3) * (Y0-Y3) will be in Z0-Z7
// Inputs get overwritten, except X2-X3 and Y2-Y3
#define mul256x256karatsuba(X, X0, X1, X2, X3, Y0, Y1, Y2, Y3, Z0, Z1, Z2, Z3, Z4, Z5, Z6, Z7, T0, T1)\
ADDS X2, X0 \ // xH + xL, destroys xL
ADCS X3, X1 \
ADCS ZR, ZR, T0 \
\
ADDS Y2, Y0, Z6 \ // yH + yL
ADCS Y3, Y1, T1 \
ADC ZR, ZR, Z7 \
\
SUB T0, ZR, Z2 \
SUB Z7, ZR, Z3 \
AND Z7, T0 \ // combined carry
\
AND Z2, Z6, Z0 \ // masked(yH + yL)
AND Z2, T1, Z1 \
\
AND Z3, X0, Z4 \ // masked(xH + xL)
AND Z3, X1, Z5 \
\
MUL Z6, X0, Z2 \
MUL T1, X0, Z3 \
\
ADDS Z4, Z0 \
UMULH T1, X0, Z4 \
ADCS Z5, Z1 \
UMULH Z6, X0, Z5 \
ADC ZR, T0 \
\ // (xH + xL) * (yH + yL)
mul128x128comba(X0, X1, Z6, T1, Z2, Z3, Z4, Z5, Z7)\
\
LDP 0+X, (X0, X1) \
\
ADDS Z0, Z4 \
UMULH Y0, X0, Z7 \
UMULH Y1, X0, T1 \
ADCS Z1, Z5 \
MUL Y0, X0, Z0 \
MUL Y1, X0, Z1 \
ADC ZR, T0 \
\ // xL * yL
mul128x128comba(X0, X1, Y0, Y1, Z0, Z1, T1, Z7, Z6)\
\
MUL Y2, X2, X0 \
UMULH Y2, X2, Y0 \
SUBS Z0, Z2 \ // (xH + xL) * (yH + yL) - xL * yL
SBCS Z1, Z3 \
SBCS T1, Z4 \
MUL Y3, X2, X1 \
UMULH Y3, X2, Z6 \
SBCS Z7, Z5 \
SBCS ZR, T0 \
\ // xH * yH
mul128x128comba(X2, X3, Y2, Y3, X0, X1, Z6, Y0, Y1)\
\
SUBS X0, Z2 \ // (xH + xL) * (yH + yL) - xL * yL - xH * yH
SBCS X1, Z3 \
SBCS Z6, Z4 \
SBCS Y0, Z5 \
SBCS ZR, T0 \
\
ADDS T1, Z2 \ // (xH * yH) * 2^256 + ((xH + xL) * (yH + yL) - xL * yL - xH * yH) * 2^128 + xL * yL
ADCS Z7, Z3 \
ADCS X0, Z4 \
ADCS X1, Z5 \
ADCS T0, Z6 \
ADC Y0, ZR, Z7
// This implements two-level Karatsuba with a 128x128 Comba multiplier
// at the bottom
TEXT ·fp503Mul(SB), NOSPLIT, $0-24
MOVD z+0(FP), R2
MOVD x+8(FP), R0
MOVD y+16(FP), R1
// Load xL in R3-R6, xH in R7-R10
// (xH + xL) in R25-R29
LDP 0(R0), (R3, R4)
LDP 32(R0), (R7, R8)
ADDS R3, R7, R25
ADCS R4, R8, R26
LDP 16(R0), (R5, R6)
LDP 48(R0), (R9, R10)
ADCS R5, R9, R27
ADCS R6, R10, R29
ADC ZR, ZR, R7
// Load yL in R11-R14, yH in R15-19
// (yH + yL) in R11-R14, destroys yL
LDP 0(R1), (R11, R12)
LDP 32(R1), (R15, R16)
ADDS R15, R11
ADCS R16, R12
LDP 16(R1), (R13, R14)
LDP 48(R1), (R17, R19)
ADCS R17, R13
ADCS R19, R14
ADC ZR, ZR, R8
// Compute maskes and combined carry
SUB R7, ZR, R9
SUB R8, ZR, R10
AND R8, R7
// masked(yH + yL)
AND R9, R11, R15
AND R9, R12, R16
AND R9, R13, R17
AND R9, R14, R19
// masked(xH + xL)
AND R10, R25, R20
AND R10, R26, R21
AND R10, R27, R22
AND R10, R29, R23
// masked(xH + xL) + masked(yH + yL) in R15-R19
ADDS R20, R15
ADCS R21, R16
ADCS R22, R17
ADCS R23, R19
ADC ZR, R7
// Use z as temporary storage
STP (R25, R26), 0(R2)
// (xH + xL) * (yH + yL)
mul256x256karatsuba(0(R2), R25, R26, R27, R29, R11, R12, R13, R14, R8, R9, R10, R20, R21, R22, R23, R24, R0, R1)
MOVD x+8(FP), R0
MOVD y+16(FP), R1
ADDS R21, R15
ADCS R22, R16
ADCS R23, R17
ADCS R24, R19
ADC ZR, R7
// Load yL in R11-R14
LDP 0(R1), (R11, R12)
LDP 16(R1), (R13, R14)
// xL * yL
mul256x256karatsuba(0(R0), R3, R4, R5, R6, R11, R12, R13, R14, R21, R22, R23, R24, R25, R26, R27, R29, R1, R2)
MOVD z+0(FP), R2
MOVD y+16(FP), R1
// (xH + xL) * (yH + yL) - xL * yL
SUBS R21, R8
SBCS R22, R9
STP (R21, R22), 0(R2)
SBCS R23, R10
SBCS R24, R20
STP (R23, R24), 16(R2)
SBCS R25, R15
SBCS R26, R16
SBCS R27, R17
SBCS R29, R19
SBC ZR, R7
// Load xH in R3-R6, yH in R11-R14
LDP 32(R0), (R3, R4)
LDP 48(R0), (R5, R6)
LDP 32(R1), (R11, R12)
LDP 48(R1), (R13, R14)
ADDS R25, R8
ADCS R26, R9
ADCS R27, R10
ADCS R29, R20
ADC ZR, ZR, R1
MOVD R20, 32(R2)
// xH * yH
mul256x256karatsuba(32(R0), R3, R4, R5, R6, R11, R12, R13, R14, R21, R22, R23, R24, R25, R26, R27, R29, R2, R20)
NEG R1, R1
MOVD z+0(FP), R2
MOVD 32(R2), R20
// (xH + xL) * (yH + yL) - xL * yL - xH * yH in R8-R10,R20,R15-R19
// Store lower half in z, that's done
SUBS R21, R8
SBCS R22, R9
STP (R8, R9), 32(R2)
SBCS R23, R10
SBCS R24, R20
STP (R10, R20), 48(R2)
SBCS R25, R15
SBCS R26, R16
SBCS R27, R17
SBCS R29, R19
SBC ZR, R7
// (xH * yH) * 2^512 + ((xH + xL) * (yH + yL) - xL * yL - xH * yH) * 2^256 + xL * yL
// Store remaining limbs in z
ADDS $1, R1
ADCS R21, R15
ADCS R22, R16
STP (R15, R16), 64(R2)
ADCS R23, R17
ADCS R24, R19
STP (R17, R19), 80(R2)
ADCS R7, R25
ADCS ZR, R26
STP (R25, R26), 96(R2)
ADCS ZR, R27
ADC ZR, R29
STP (R27, R29), 112(R2)
RET
// Expects that X0*Y0 is already in Z0(low),Z3(high) and X0*Y1 in Z1(low),Z2(high)
// Z0 is not actually touched
// Result of (X0-X1) * (Y0-Y3) will be in Z0-Z5
// Inputs remain intact
#define mul128x256comba(X0, X1, Y0, Y1, Y2, Y3, Z0, Z1, Z2, Z3, Z4, Z5, T0, T1, T2, T3)\
MUL X1, Y0, T0 \
UMULH X1, Y0, T1 \
ADDS Z3, Z1 \
ADC ZR, Z2 \
\
MUL X0, Y2, T2 \
UMULH X0, Y2, T3 \
ADDS T0, Z1 \
ADCS T1, Z2 \
ADC ZR, ZR, Z3 \
\
MUL X1, Y1, T0 \
UMULH X1, Y1, T1 \
ADDS T2, Z2 \
ADCS T3, Z3 \
ADC ZR, ZR, Z4 \
\
MUL X0, Y3, T2 \
UMULH X0, Y3, T3 \
ADDS T0, Z2 \
ADCS T1, Z3 \
ADC ZR, Z4 \
\
MUL X1, Y2, T0 \
UMULH X1, Y2, T1 \
ADDS T2, Z3 \
ADCS T3, Z4 \
ADC ZR, ZR, Z5 \
\
MUL X1, Y3, T2 \
UMULH X1, Y3, T3 \
ADDS T0, Z3 \
ADCS T1, Z4 \
ADC ZR, Z5 \
ADDS T2, Z4 \
ADC T3, Z5
// This implements the shifted 2^(B*w) Montgomery reduction from
// https://eprint.iacr.org/2016/986.pdf, section Section 3.2, with
// B = 4, w = 64. Performance results were reported in
// https://eprint.iacr.org/2018/700.pdf Section 6.
TEXT ·fp503MontgomeryReduce(SB), NOSPLIT, $0-16
MOVD x+8(FP), R0
// Load x0-x1
LDP 0(R0), (R2, R3)
// Load the prime constant in R25-R29
LDP ·p503p1s8+32(SB), (R25, R26)
LDP ·p503p1s8+48(SB), (R27, R29)
// [x0,x1] * p503p1s8 to R4-R9
MUL R2, R25, R4 // x0 * p503p1s8[0]
UMULH R2, R25, R7
MUL R2, R26, R5 // x0 * p503p1s8[1]
UMULH R2, R26, R6
mul128x256comba(R2, R3, R25, R26, R27, R29, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13)
LDP 16(R0), (R3, R11) // x2
LDP 32(R0), (R12, R13)
LDP 48(R0), (R14, R15)
// Left-shift result in R4-R9 by 56 to R4-R10
ORR R9>>8, ZR, R10
LSL $56, R9
ORR R8>>8, R9
LSL $56, R8
ORR R7>>8, R8
LSL $56, R7
ORR R6>>8, R7
LSL $56, R6
ORR R5>>8, R6
LSL $56, R5
ORR R4>>8, R5
LSL $56, R4
ADDS R4, R11 // x3
ADCS R5, R12 // x4
ADCS R6, R13
ADCS R7, R14
ADCS R8, R15
LDP 64(R0), (R16, R17)
LDP 80(R0), (R19, R20)
MUL R3, R25, R4 // x2 * p503p1s8[0]
UMULH R3, R25, R7
ADCS R9, R16
ADCS R10, R17
ADCS ZR, R19
ADCS ZR, R20
LDP 96(R0), (R21, R22)
LDP 112(R0), (R23, R24)
MUL R3, R26, R5 // x2 * p503p1s8[1]
UMULH R3, R26, R6
ADCS ZR, R21
ADCS ZR, R22
ADCS ZR, R23
ADC ZR, R24
// [x2,x3] * p503p1s8 to R4-R9
mul128x256comba(R3, R11, R25, R26, R27, R29, R4, R5, R6, R7, R8, R9, R10, R0, R1, R2)
ORR R9>>8, ZR, R10
LSL $56, R9
ORR R8>>8, R9
LSL $56, R8
ORR R7>>8, R8
LSL $56, R7
ORR R6>>8, R7
LSL $56, R6
ORR R5>>8, R6
LSL $56, R5
ORR R4>>8, R5
LSL $56, R4
ADDS R4, R13 // x5
ADCS R5, R14 // x6
ADCS R6, R15
ADCS R7, R16
MUL R12, R25, R4 // x4 * p503p1s8[0]
UMULH R12, R25, R7
ADCS R8, R17
ADCS R9, R19
ADCS R10, R20
ADCS ZR, R21
MUL R12, R26, R5 // x4 * p503p1s8[1]
UMULH R12, R26, R6
ADCS ZR, R22
ADCS ZR, R23
ADC ZR, R24
// [x4,x5] * p503p1s8 to R4-R9
mul128x256comba(R12, R13, R25, R26, R27, R29, R4, R5, R6, R7, R8, R9, R10, R0, R1, R2)
ORR R9>>8, ZR, R10
LSL $56, R9
ORR R8>>8, R9
LSL $56, R8
ORR R7>>8, R8
LSL $56, R7
ORR R6>>8, R7
LSL $56, R6
ORR R5>>8, R6
LSL $56, R5
ORR R4>>8, R5
LSL $56, R4
ADDS R4, R15 // x7
ADCS R5, R16 // x8
ADCS R6, R17
ADCS R7, R19
MUL R14, R25, R4 // x6 * p503p1s8[0]
UMULH R14, R25, R7
ADCS R8, R20
ADCS R9, R21
ADCS R10, R22
MUL R14, R26, R5 // x6 * p503p1s8[1]
UMULH R14, R26, R6
ADCS ZR, R23
ADC ZR, R24
// [x6,x7] * p503p1s8 to R4-R9
mul128x256comba(R14, R15, R25, R26, R27, R29, R4, R5, R6, R7, R8, R9, R10, R0, R1, R2)
ORR R9>>8, ZR, R10
LSL $56, R9
ORR R8>>8, R9
LSL $56, R8
ORR R7>>8, R8
LSL $56, R7
ORR R6>>8, R7
LSL $56, R6
ORR R5>>8, R6
LSL $56, R5
ORR R4>>8, R5
LSL $56, R4
MOVD z+0(FP), R0
ADDS R4, R17
ADCS R5, R19
STP (R16, R17), 0(R0) // Store final result to z
ADCS R6, R20
ADCS R7, R21
STP (R19, R20), 16(R0)
ADCS R8, R22
ADCS R9, R23
STP (R21, R22), 32(R0)
ADC R10, R24
STP (R23, R24), 48(R0)
RET
TEXT ·fp503StrongReduce(SB), NOSPLIT, $0-8
MOVD x+0(FP), R0
// Keep x in R1-R8, p503 in R9-R14, subtract to R1-R8
LDP ·p503+16(SB), (R9, R10)
LDP 0(R0), (R1, R2)
LDP 16(R0), (R3, R4)
SUBS R9, R1
SBCS R9, R2
LDP 32(R0), (R5, R6)
LDP ·p503+32(SB), (R11, R12)
SBCS R9, R3
SBCS R10, R4
LDP 48(R0), (R7, R8)
LDP ·p503+48(SB), (R13, R14)
SBCS R11, R5
SBCS R12, R6
SBCS R13, R7
SBCS R14, R8
SBC ZR, ZR, R15
// Mask with the borrow and add p503
AND R15, R9
AND R15, R10
AND R15, R11
AND R15, R12
AND R15, R13
AND R15, R14
ADDS R9, R1
ADCS R9, R2
STP (R1, R2), 0(R0)
ADCS R9, R3
ADCS R10, R4
STP (R3, R4), 16(R0)
ADCS R11, R5
ADCS R12, R6
STP (R5, R6), 32(R0)
ADCS R13, R7
ADCS R14, R8
STP (R7, R8), 48(R0)
RET