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| author | eric fang <eric.fang@arm.com> | 2022-01-05 09:20:06 +0000 |
|---|---|---|
| committer | Eric Fang <eric.fang@arm.com> | 2022-01-17 09:23:25 +0000 |
| commit | 897b3da2e079b9b940b309747305a5379fffa6ec (patch) | |
| tree | ca48cbb2f1e03c0803243e1bda717c08e35db6cb | |
| parent | 3b5eec937018be98549dea7067964018f0e5824c (diff) | |
| download | go-897b3da2e079b9b940b309747305a5379fffa6ec.tar.gz go-897b3da2e079b9b940b309747305a5379fffa6ec.zip | |
cmd/internal/obj/arm64: adjust rule for VMOVQ instruction
The VMOVQ instruction stores a 128-bit number into a V register, for
example:
VMOVQ $0x1122334455667788, $0x99aabbccddeeff00, V2
From a documentation (https://pkg.go.dev/cmd/internal/obj/arm64) point
of view, the value in V2 should be 0x112233445566778899aabbccddeeff00,
however the value is actually 0x99aabbccddeeff001122334455667788. The
reason is that we misplaced the high 64-bit and the low 64-bit in the
literal pool. To maintain backward compatibility, this CL adjusts the
rule of VMOVQ instruction to make the documentation consistent with the
code.
Fixes #50528
Change-Id: Ib51f59e97c55252ab2a50bbc6ba4d430732a7a04
Reviewed-on: https://go-review.googlesource.com/c/go/+/377055
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Eric Fang <eric.fang@arm.com>
Run-TryBot: Eric Fang <eric.fang@arm.com>
Trust: Eric Fang <eric.fang@arm.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
| -rw-r--r-- | src/cmd/internal/obj/arm64/asm7.go | 2 | ||||
| -rw-r--r-- | src/cmd/internal/obj/arm64/doc.go | 4 |
2 files changed, 3 insertions, 3 deletions
diff --git a/src/cmd/internal/obj/arm64/asm7.go b/src/cmd/internal/obj/arm64/asm7.go index 68f0921d4d..f4111f4f5c 100644 --- a/src/cmd/internal/obj/arm64/asm7.go +++ b/src/cmd/internal/obj/arm64/asm7.go @@ -1184,7 +1184,7 @@ func (c *ctxt7) addpool128(p *obj.Prog, al, ah *obj.Addr) { q := c.newprog() q.As = ADWORD q.To.Type = obj.TYPE_CONST - q.To.Offset = al.Offset + q.To.Offset = al.Offset // q.Pc is lower than t.Pc, so al.Offset is stored in q. t := c.newprog() t.As = ADWORD diff --git a/src/cmd/internal/obj/arm64/doc.go b/src/cmd/internal/obj/arm64/doc.go index 14f0f4c616..1234a3e818 100644 --- a/src/cmd/internal/obj/arm64/doc.go +++ b/src/cmd/internal/obj/arm64/doc.go @@ -89,12 +89,12 @@ In the following example, PCALIGN at the entry of the function Add will align it 7. Move large constants to vector registers. Go asm uses VMOVQ/VMOVD/VMOVS to move 128-bit, 64-bit and 32-bit constants into vector registers, respectively. -And for a 128-bit interger, it take two 64-bit operands, for the high and low parts separately. +And for a 128-bit interger, it take two 64-bit operands, for the low and high parts separately. Examples: VMOVS $0x11223344, V0 VMOVD $0x1122334455667788, V1 - VMOVQ $0x1122334455667788, $8877665544332211, V2 // V2=0x11223344556677888877665544332211 + VMOVQ $0x1122334455667788, $0x99aabbccddeeff00, V2 // V2=0x99aabbccddeeff001122334455667788 8. Move an optionally-shifted 16-bit immediate value to a register. |