syncthing/vendor/github.com/remyoudompheng/bigfft/arith_amd64.s

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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// This file provides fast assembly versions for the elementary
// arithmetic operations on vectors implemented in arith.go.
// func mulWW(x, y Word) (z1, z0 Word)
TEXT ·mulWW(SB),7,$0
MOVQ x+0(FP), AX
MULQ y+8(FP)
MOVQ DX, z1+16(FP)
MOVQ AX, z0+24(FP)
RET
// func divWW(x1, x0, y Word) (q, r Word)
TEXT ·divWW(SB),7,$0
MOVQ x1+0(FP), DX
MOVQ x0+8(FP), AX
DIVQ y+16(FP)
MOVQ AX, q+24(FP)
MOVQ DX, r+32(FP)
RET
// The carry bit is saved with SBBQ Rx, Rx: if the carry was set, Rx is -1, otherwise it is 0.
// It is restored with ADDQ Rx, Rx: if Rx was -1 the carry is set, otherwise it is cleared.
// This is faster than using rotate instructions.
//
// CAUTION: Note that MOVQ $0, Rx is translated to XORQ Rx, Rx which clears the carry bit!
// func addVV(z, x, y []Word) (c Word)
TEXT ·addVV(SB),7,$0
MOVQ z_len+8(FP), DI
MOVQ x+24(FP), R8
MOVQ y+48(FP), R9
MOVQ z+0(FP), R10
MOVQ $0, CX // c = 0
MOVQ $0, SI // i = 0
// s/JL/JMP/ below to disable the unrolled loop
SUBQ $4, DI // n -= 4
JL V1 // if n < 0 goto V1
U1: // n >= 0
// regular loop body unrolled 4x
ADDQ CX, CX // restore CF
MOVQ 0(R8)(SI*8), R11
MOVQ 8(R8)(SI*8), R12
MOVQ 16(R8)(SI*8), R13
MOVQ 24(R8)(SI*8), R14
ADCQ 0(R9)(SI*8), R11
ADCQ 8(R9)(SI*8), R12
ADCQ 16(R9)(SI*8), R13
ADCQ 24(R9)(SI*8), R14
MOVQ R11, 0(R10)(SI*8)
MOVQ R12, 8(R10)(SI*8)
MOVQ R13, 16(R10)(SI*8)
MOVQ R14, 24(R10)(SI*8)
SBBQ CX, CX // save CF
ADDQ $4, SI // i += 4
SUBQ $4, DI // n -= 4
JGE U1 // if n >= 0 goto U1
V1: ADDQ $4, DI // n += 4
JLE E1 // if n <= 0 goto E1
L1: // n > 0
ADDQ CX, CX // restore CF
MOVQ 0(R8)(SI*8), R11
ADCQ 0(R9)(SI*8), R11
MOVQ R11, 0(R10)(SI*8)
SBBQ CX, CX // save CF
ADDQ $1, SI // i++
SUBQ $1, DI // n--
JG L1 // if n > 0 goto L1
E1: NEGQ CX
MOVQ CX, c+72(FP) // return c
RET
// func subVV(z, x, y []Word) (c Word)
// (same as addVV except for SBBQ instead of ADCQ and label names)
TEXT ·subVV(SB),7,$0
MOVQ z_len+8(FP), DI
MOVQ x+24(FP), R8
MOVQ y+48(FP), R9
MOVQ z+0(FP), R10
MOVQ $0, CX // c = 0
MOVQ $0, SI // i = 0
// s/JL/JMP/ below to disable the unrolled loop
SUBQ $4, DI // n -= 4
JL V2 // if n < 0 goto V2
U2: // n >= 0
// regular loop body unrolled 4x
ADDQ CX, CX // restore CF
MOVQ 0(R8)(SI*8), R11
MOVQ 8(R8)(SI*8), R12
MOVQ 16(R8)(SI*8), R13
MOVQ 24(R8)(SI*8), R14
SBBQ 0(R9)(SI*8), R11
SBBQ 8(R9)(SI*8), R12
SBBQ 16(R9)(SI*8), R13
SBBQ 24(R9)(SI*8), R14
MOVQ R11, 0(R10)(SI*8)
MOVQ R12, 8(R10)(SI*8)
MOVQ R13, 16(R10)(SI*8)
MOVQ R14, 24(R10)(SI*8)
SBBQ CX, CX // save CF
ADDQ $4, SI // i += 4
SUBQ $4, DI // n -= 4
JGE U2 // if n >= 0 goto U2
V2: ADDQ $4, DI // n += 4
JLE E2 // if n <= 0 goto E2
L2: // n > 0
ADDQ CX, CX // restore CF
MOVQ 0(R8)(SI*8), R11
SBBQ 0(R9)(SI*8), R11
MOVQ R11, 0(R10)(SI*8)
SBBQ CX, CX // save CF
ADDQ $1, SI // i++
SUBQ $1, DI // n--
JG L2 // if n > 0 goto L2
E2: NEGQ CX
MOVQ CX, c+72(FP) // return c
RET
// func addVW(z, x []Word, y Word) (c Word)
TEXT ·addVW(SB),7,$0
MOVQ z_len+8(FP), DI
MOVQ x+24(FP), R8
MOVQ y+48(FP), CX // c = y
MOVQ z+0(FP), R10
MOVQ $0, SI // i = 0
// s/JL/JMP/ below to disable the unrolled loop
SUBQ $4, DI // n -= 4
JL V3 // if n < 4 goto V3
U3: // n >= 0
// regular loop body unrolled 4x
MOVQ 0(R8)(SI*8), R11
MOVQ 8(R8)(SI*8), R12
MOVQ 16(R8)(SI*8), R13
MOVQ 24(R8)(SI*8), R14
ADDQ CX, R11
ADCQ $0, R12
ADCQ $0, R13
ADCQ $0, R14
SBBQ CX, CX // save CF
NEGQ CX
MOVQ R11, 0(R10)(SI*8)
MOVQ R12, 8(R10)(SI*8)
MOVQ R13, 16(R10)(SI*8)
MOVQ R14, 24(R10)(SI*8)
ADDQ $4, SI // i += 4
SUBQ $4, DI // n -= 4
JGE U3 // if n >= 0 goto U3
V3: ADDQ $4, DI // n += 4
JLE E3 // if n <= 0 goto E3
L3: // n > 0
ADDQ 0(R8)(SI*8), CX
MOVQ CX, 0(R10)(SI*8)
SBBQ CX, CX // save CF
NEGQ CX
ADDQ $1, SI // i++
SUBQ $1, DI // n--
JG L3 // if n > 0 goto L3
E3: MOVQ CX, c+56(FP) // return c
RET
// func subVW(z, x []Word, y Word) (c Word)
// (same as addVW except for SUBQ/SBBQ instead of ADDQ/ADCQ and label names)
TEXT ·subVW(SB),7,$0
MOVQ z_len+8(FP), DI
MOVQ x+24(FP), R8
MOVQ y+48(FP), CX // c = y
MOVQ z+0(FP), R10
MOVQ $0, SI // i = 0
// s/JL/JMP/ below to disable the unrolled loop
SUBQ $4, DI // n -= 4
JL V4 // if n < 4 goto V4
U4: // n >= 0
// regular loop body unrolled 4x
MOVQ 0(R8)(SI*8), R11
MOVQ 8(R8)(SI*8), R12
MOVQ 16(R8)(SI*8), R13
MOVQ 24(R8)(SI*8), R14
SUBQ CX, R11
SBBQ $0, R12
SBBQ $0, R13
SBBQ $0, R14
SBBQ CX, CX // save CF
NEGQ CX
MOVQ R11, 0(R10)(SI*8)
MOVQ R12, 8(R10)(SI*8)
MOVQ R13, 16(R10)(SI*8)
MOVQ R14, 24(R10)(SI*8)
ADDQ $4, SI // i += 4
SUBQ $4, DI // n -= 4
JGE U4 // if n >= 0 goto U4
V4: ADDQ $4, DI // n += 4
JLE E4 // if n <= 0 goto E4
L4: // n > 0
MOVQ 0(R8)(SI*8), R11
SUBQ CX, R11
MOVQ R11, 0(R10)(SI*8)
SBBQ CX, CX // save CF
NEGQ CX
ADDQ $1, SI // i++
SUBQ $1, DI // n--
JG L4 // if n > 0 goto L4
E4: MOVQ CX, c+56(FP) // return c
RET
// func shlVU(z, x []Word, s uint) (c Word)
TEXT ·shlVU(SB),7,$0
MOVQ z_len+8(FP), BX // i = z
SUBQ $1, BX // i--
JL X8b // i < 0 (n <= 0)
// n > 0
MOVQ z+0(FP), R10
MOVQ x+24(FP), R8
MOVQ s+48(FP), CX
MOVQ (R8)(BX*8), AX // w1 = x[n-1]
MOVQ $0, DX
SHLQ CX, DX:AX // w1>>ŝ
MOVQ DX, c+56(FP)
CMPQ BX, $0
JLE X8a // i <= 0
// i > 0
L8: MOVQ AX, DX // w = w1
MOVQ -8(R8)(BX*8), AX // w1 = x[i-1]
SHLQ CX, DX:AX // w<<s | w1>>ŝ
MOVQ DX, (R10)(BX*8) // z[i] = w<<s | w1>>ŝ
SUBQ $1, BX // i--
JG L8 // i > 0
// i <= 0
X8a: SHLQ CX, AX // w1<<s
MOVQ AX, (R10) // z[0] = w1<<s
RET
X8b: MOVQ $0, c+56(FP)
RET
// func shrVU(z, x []Word, s uint) (c Word)
TEXT ·shrVU(SB),7,$0
MOVQ z_len+8(FP), R11
SUBQ $1, R11 // n--
JL X9b // n < 0 (n <= 0)
// n > 0
MOVQ z+0(FP), R10
MOVQ x+24(FP), R8
MOVQ s+48(FP), CX
MOVQ (R8), AX // w1 = x[0]
MOVQ $0, DX
SHRQ CX, DX:AX // w1<<ŝ
MOVQ DX, c+56(FP)
MOVQ $0, BX // i = 0
JMP E9
// i < n-1
L9: MOVQ AX, DX // w = w1
MOVQ 8(R8)(BX*8), AX // w1 = x[i+1]
SHRQ CX, DX:AX // w>>s | w1<<ŝ
MOVQ DX, (R10)(BX*8) // z[i] = w>>s | w1<<ŝ
ADDQ $1, BX // i++
E9: CMPQ BX, R11
JL L9 // i < n-1
// i >= n-1
X9a: SHRQ CX, AX // w1>>s
MOVQ AX, (R10)(R11*8) // z[n-1] = w1>>s
RET
X9b: MOVQ $0, c+56(FP)
RET
// func mulAddVWW(z, x []Word, y, r Word) (c Word)
TEXT ·mulAddVWW(SB),7,$0
MOVQ z+0(FP), R10
MOVQ x+24(FP), R8
MOVQ y+48(FP), R9
MOVQ r+56(FP), CX // c = r
MOVQ z_len+8(FP), R11
MOVQ $0, BX // i = 0
CMPQ R11, $4
JL E5
U5: // i+4 <= n
// regular loop body unrolled 4x
MOVQ (0*8)(R8)(BX*8), AX
MULQ R9
ADDQ CX, AX
ADCQ $0, DX
MOVQ AX, (0*8)(R10)(BX*8)
MOVQ DX, CX
MOVQ (1*8)(R8)(BX*8), AX
MULQ R9
ADDQ CX, AX
ADCQ $0, DX
MOVQ AX, (1*8)(R10)(BX*8)
MOVQ DX, CX
MOVQ (2*8)(R8)(BX*8), AX
MULQ R9
ADDQ CX, AX
ADCQ $0, DX
MOVQ AX, (2*8)(R10)(BX*8)
MOVQ DX, CX
MOVQ (3*8)(R8)(BX*8), AX
MULQ R9
ADDQ CX, AX
ADCQ $0, DX
MOVQ AX, (3*8)(R10)(BX*8)
MOVQ DX, CX
ADDQ $4, BX // i += 4
LEAQ 4(BX), DX
CMPQ DX, R11
JLE U5
JMP E5
L5: MOVQ (R8)(BX*8), AX
MULQ R9
ADDQ CX, AX
ADCQ $0, DX
MOVQ AX, (R10)(BX*8)
MOVQ DX, CX
ADDQ $1, BX // i++
E5: CMPQ BX, R11 // i < n
JL L5
MOVQ CX, c+64(FP)
RET
// func addMulVVW(z, x []Word, y Word) (c Word)
TEXT ·addMulVVW(SB),7,$0
MOVQ z+0(FP), R10
MOVQ x+24(FP), R8
MOVQ y+48(FP), R9
MOVQ z_len+8(FP), R11
MOVQ $0, BX // i = 0
MOVQ $0, CX // c = 0
MOVQ R11, R12
ANDQ $-2, R12
CMPQ R11, $2
JAE A6
JMP E6
A6:
MOVQ (R8)(BX*8), AX
MULQ R9
ADDQ (R10)(BX*8), AX
ADCQ $0, DX
ADDQ CX, AX
ADCQ $0, DX
MOVQ DX, CX
MOVQ AX, (R10)(BX*8)
MOVQ (8)(R8)(BX*8), AX
MULQ R9
ADDQ (8)(R10)(BX*8), AX
ADCQ $0, DX
ADDQ CX, AX
ADCQ $0, DX
MOVQ DX, CX
MOVQ AX, (8)(R10)(BX*8)
ADDQ $2, BX
CMPQ BX, R12
JL A6
JMP E6
L6: MOVQ (R8)(BX*8), AX
MULQ R9
ADDQ CX, AX
ADCQ $0, DX
ADDQ AX, (R10)(BX*8)
ADCQ $0, DX
MOVQ DX, CX
ADDQ $1, BX // i++
E6: CMPQ BX, R11 // i < n
JL L6
MOVQ CX, c+56(FP)
RET
// func divWVW(z []Word, xn Word, x []Word, y Word) (r Word)
TEXT ·divWVW(SB),7,$0
MOVQ z+0(FP), R10
MOVQ xn+24(FP), DX // r = xn
MOVQ x+32(FP), R8
MOVQ y+56(FP), R9
MOVQ z_len+8(FP), BX // i = z
JMP E7
L7: MOVQ (R8)(BX*8), AX
DIVQ R9
MOVQ AX, (R10)(BX*8)
E7: SUBQ $1, BX // i--
JGE L7 // i >= 0
MOVQ DX, r+64(FP)
RET