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cmd/internal/obj/riscv: fix LMUL encoding for MF2 and MF8 

The encodings for the riscv64 special operands SPOP_MF2 and SPOP_MF8
are incorrect, i.e., their values are swapped.  This leads to
incorrect encodings for the VSETVLI and VSETIVLI instructions.  The
assembler currently encodes

VSETVLI	X10, E32, MF8, TA, MA, X12

as

VSETVLI	X10, E32, MF2, TA, MA, X12

We update the encodings for SPOP_MF2 and SPOP_MF8 so that they match
the LMUL table in section "31.3.4. Vector type register, vtype" of
the "RISC-V Instruction Set Manual Volume 1".

Change-Id: Ic73355533d7c2a901ee060b35c2f7af6d58453e4
Reviewed-on: https://go-review.googlesource.com/c/go/+/670016
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Reviewed-by: Meng Zhuo <mengzhuo1203@gmail.com>
Reviewed-by: Joel Sing <joel@sing.id.au>
This commit is contained in:
Mark Ryan 2025-05-06 13:02:34 +02:00
parent d13da63929
commit 5a1f47a7f7
2 changed files with 4 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
src/cmd/asm/internal/asm/testdata/riscv64.s vendored
View File

@ -438,9 +438,9 @@ start:
VSETVLI X10, E32, M2, TA, MA, X12 // 5776150d
VSETVLI X10, E32, M4, TA, MA, X12 // 5776250d
VSETVLI X10, E32, M8, TA, MA, X12 // 5776350d
VSETVLI X10, E32, MF2, TA, MA, X12 // 5776550d
VSETVLI X10, E32, MF8, TA, MA, X12 // 5776550d
VSETVLI X10, E32, MF4, TA, MA, X12 // 5776650d
VSETVLI X10, E32, MF8, TA, MA, X12 // 5776750d
VSETVLI X10, E32, MF2, TA, MA, X12 // 5776750d
VSETVLI X10, E32, M1, TA, MA, X12 // 5776050d
VSETVLI $15, E32, M1, TA, MA, X12 // 57f607cd
VSETIVLI $0, E32, M1, TA, MA, X12 // 577600cd

4
src/cmd/internal/obj/riscv/cpu.go
View File

@ -1297,9 +1297,9 @@ var specialOperands = map[SpecialOperand]struct {
SPOP_M2: {encoding: 1, name: "M2"},
SPOP_M4: {encoding: 2, name: "M4"},
SPOP_M8: {encoding: 3, name: "M8"},
SPOP_MF2: {encoding: 5, name: "MF2"},
SPOP_MF8: {encoding: 5, name: "MF8"},
SPOP_MF4: {encoding: 6, name: "MF4"},
SPOP_MF8: {encoding: 7, name: "MF8"},
SPOP_MF2: {encoding: 7, name: "MF2"},
SPOP_E8: {encoding: 0, name: "E8"},
SPOP_E16: {encoding: 1, name: "E16"},