mirror of
https://github.com/golang/go
synced 2024-11-18 15:54:42 -07:00
50b11318fe
This optimization works on any integer with exactly one bit set. This is identical to being a power of two, except in the most negative number. Use oneBit instead. The rule now triggers in a few more places in std+cmd, in packages encoding/asn1, crypto/elliptic, and vendor/golang.org/x/crypto/cryptobyte. This change obviates the need for CL 222479 by doing this optimization consistently in the compiler. Change-Id: I983c6235290fdc634fda5e11b10f1f8ce041272f Reviewed-on: https://go-review.googlesource.com/c/go/+/229124 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
334 lines
5.3 KiB
Go
334 lines
5.3 KiB
Go
// asmcheck
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// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package codegen
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/************************************
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* 64-bit instructions
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************************************/
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func bitcheck64_constleft(a uint64) (n int) {
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// amd64:"BTQ\t[$]63"
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if a&(1<<63) != 0 {
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return 1
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}
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// amd64:"BTQ\t[$]60"
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if a&(1<<60) != 0 {
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return 1
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}
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// amd64:"BTL\t[$]0"
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if a&(1<<0) != 0 {
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return 1
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}
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return 0
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}
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func bitcheck64_constright(a [8]uint64) (n int) {
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// amd64:"BTQ\t[$]63"
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if (a[0]>>63)&1 != 0 {
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return 1
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}
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// amd64:"BTQ\t[$]63"
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if a[1]>>63 != 0 {
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return 1
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}
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// amd64:"BTQ\t[$]63"
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if a[2]>>63 == 0 {
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return 1
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}
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// amd64:"BTQ\t[$]60"
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if (a[3]>>60)&1 == 0 {
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return 1
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}
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// amd64:"BTL\t[$]1"
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if (a[4]>>1)&1 == 0 {
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return 1
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}
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// amd64:"BTL\t[$]0"
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if (a[5]>>0)&1 == 0 {
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return 1
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}
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// amd64:"BTL\t[$]7"
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if (a[6]>>5)&4 == 0 {
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return 1
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}
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return 0
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}
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func bitcheck64_var(a, b uint64) (n int) {
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// amd64:"BTQ"
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if a&(1<<(b&63)) != 0 {
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return 1
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}
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// amd64:"BTQ",-"BT.\t[$]0"
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if (b>>(a&63))&1 != 0 {
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return 1
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}
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return 0
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}
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func bitcheck64_mask(a uint64) (n int) {
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// amd64:"BTQ\t[$]63"
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if a&0x8000000000000000 != 0 {
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return 1
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}
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// amd64:"BTQ\t[$]59"
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if a&0x800000000000000 != 0 {
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return 1
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}
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// amd64:"BTL\t[$]0"
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if a&0x1 != 0 {
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return 1
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}
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return 0
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}
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func biton64(a, b uint64) (n uint64) {
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// amd64:"BTSQ"
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n += b | (1 << (a & 63))
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// amd64:"BTSQ\t[$]63"
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n += a | (1 << 63)
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// amd64:"BTSQ\t[$]60"
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n += a | (1 << 60)
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// amd64:"ORQ\t[$]1"
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n += a | (1 << 0)
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return n
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}
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func bitoff64(a, b uint64) (n uint64) {
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// amd64:"BTRQ"
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n += b &^ (1 << (a & 63))
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// amd64:"BTRQ\t[$]63"
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n += a &^ (1 << 63)
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// amd64:"BTRQ\t[$]60"
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n += a &^ (1 << 60)
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// amd64:"ANDQ\t[$]-2"
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n += a &^ (1 << 0)
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return n
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}
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func bitcompl64(a, b uint64) (n uint64) {
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// amd64:"BTCQ"
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n += b ^ (1 << (a & 63))
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// amd64:"BTCQ\t[$]63"
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n += a ^ (1 << 63)
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// amd64:"BTCQ\t[$]60"
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n += a ^ (1 << 60)
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// amd64:"XORQ\t[$]1"
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n += a ^ (1 << 0)
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return n
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}
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/************************************
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* 32-bit instructions
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************************************/
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func bitcheck32_constleft(a uint32) (n int) {
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// amd64:"BTL\t[$]31"
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if a&(1<<31) != 0 {
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return 1
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}
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// amd64:"BTL\t[$]28"
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if a&(1<<28) != 0 {
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return 1
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}
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// amd64:"BTL\t[$]0"
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if a&(1<<0) != 0 {
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return 1
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}
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return 0
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}
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func bitcheck32_constright(a [8]uint32) (n int) {
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// amd64:"BTL\t[$]31"
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if (a[0]>>31)&1 != 0 {
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return 1
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}
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// amd64:"BTL\t[$]31"
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if a[1]>>31 != 0 {
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return 1
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}
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// amd64:"BTL\t[$]31"
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if a[2]>>31 == 0 {
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return 1
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}
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// amd64:"BTL\t[$]28"
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if (a[3]>>28)&1 == 0 {
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return 1
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}
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// amd64:"BTL\t[$]1"
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if (a[4]>>1)&1 == 0 {
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return 1
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}
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// amd64:"BTL\t[$]0"
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if (a[5]>>0)&1 == 0 {
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return 1
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}
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// amd64:"BTL\t[$]7"
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if (a[6]>>5)&4 == 0 {
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return 1
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}
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return 0
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}
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func bitcheck32_var(a, b uint32) (n int) {
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// amd64:"BTL"
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if a&(1<<(b&31)) != 0 {
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return 1
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}
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// amd64:"BTL",-"BT.\t[$]0"
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if (b>>(a&31))&1 != 0 {
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return 1
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}
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return 0
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}
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func bitcheck32_mask(a uint32) (n int) {
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// amd64:"BTL\t[$]31"
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if a&0x80000000 != 0 {
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return 1
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}
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// amd64:"BTL\t[$]27"
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if a&0x8000000 != 0 {
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return 1
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}
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// amd64:"BTL\t[$]0"
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if a&0x1 != 0 {
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return 1
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}
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return 0
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}
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func biton32(a, b uint32) (n uint32) {
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// amd64:"BTSL"
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n += b | (1 << (a & 31))
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// amd64:"BTSL\t[$]31"
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n += a | (1 << 31)
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// amd64:"BTSL\t[$]28"
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n += a | (1 << 28)
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// amd64:"ORL\t[$]1"
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n += a | (1 << 0)
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return n
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}
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func bitoff32(a, b uint32) (n uint32) {
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// amd64:"BTRL"
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n += b &^ (1 << (a & 31))
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// amd64:"BTRL\t[$]31"
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n += a &^ (1 << 31)
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// amd64:"BTRL\t[$]28"
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n += a &^ (1 << 28)
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// amd64:"ANDL\t[$]-2"
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n += a &^ (1 << 0)
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return n
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}
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func bitcompl32(a, b uint32) (n uint32) {
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// amd64:"BTCL"
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n += b ^ (1 << (a & 31))
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// amd64:"BTCL\t[$]31"
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n += a ^ (1 << 31)
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// amd64:"BTCL\t[$]28"
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n += a ^ (1 << 28)
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// amd64:"XORL\t[$]1"
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n += a ^ (1 << 0)
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return n
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}
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// check direct operation on memory with constant source
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func bitOpOnMem(a []uint32) {
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// amd64:`ANDL\s[$]200,\s\([A-Z]+\)`
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a[0] &= 200
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// amd64:`ORL\s[$]220,\s4\([A-Z]+\)`
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a[1] |= 220
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// amd64:`XORL\s[$]240,\s8\([A-Z]+\)`
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a[2] ^= 240
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// amd64:`BTRL\s[$]15,\s12\([A-Z]+\)`,-`ANDL`
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a[3] &= 0xffff7fff
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// amd64:`BTSL\s[$]14,\s16\([A-Z]+\)`,-`ORL`
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a[4] |= 0x4000
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// amd64:`BTCL\s[$]13,\s20\([A-Z]+\)`,-`XORL`
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a[5] ^= 0x2000
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}
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func bitcheckMostNegative(b uint8) bool {
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// amd64:"TESTB"
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return b&0x80 == 0x80
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}
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// Check AND masking on arm64 (Issue #19857)
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func and_mask_1(a uint64) uint64 {
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// arm64:`AND\t`
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return a & ((1 << 63) - 1)
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}
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func and_mask_2(a uint64) uint64 {
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// arm64:`AND\t`
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return a & (1 << 63)
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}
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func and_mask_3(a, b uint32) (uint32, uint32) {
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// arm/7:`BIC`,-`AND`
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a &= 0xffffaaaa
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// arm/7:`BFC`,-`AND`,-`BIC`
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b &= 0xffc003ff
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return a, b
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}
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// Check generation of arm64 BIC/EON/ORN instructions
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func op_bic(x, y uint32) uint32 {
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// arm64:`BIC\t`,-`AND`
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return x &^ y
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}
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func op_eon(x, y uint32) uint32 {
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// arm64:`EON\t`,-`XOR`
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return x ^ ^y
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}
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func op_orn(x, y uint32) uint32 {
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// arm64:`ORN\t`,-`ORR`
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return x | ^y
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}
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// check bitsets
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func bitSetPowerOf2Test(x int) bool {
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// amd64:"BTL\t[$]3"
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return x&8 == 8
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}
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func bitSetTest(x int) bool {
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// amd64:"ANDQ\t[$]9, AX"
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// amd64:"CMPQ\tAX, [$]9"
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return x&9 == 9
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}
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