cmd/internal/obj/riscv: add NEG/NEGW pseudo-instructions
Provide NEG/NEGW pseudo-instructions, which translate to SUB/SUBW with the
zero register as a source.
Change-Id: I2c1ec1e75611c234c5ee8e39390dd188f8e42bae
Reviewed-on: https://go-review.googlesource.com/c/go/+/221689
Reviewed-by: Cherry Zhang <cherryyz@google.com>
diff --git a/src/cmd/asm/internal/asm/testdata/riscvenc.s b/src/cmd/asm/internal/asm/testdata/riscvenc.s
index 6ccac42..74bc43d 100644
--- a/src/cmd/asm/internal/asm/testdata/riscvenc.s
+++ b/src/cmd/asm/internal/asm/testdata/riscvenc.s
@@ -309,10 +309,16 @@
NOT X5 // 93c2f2ff
NOT X5, X6 // 13c3f2ff
+ // NEG/NEGW pseudo-instructions
+ NEG X5 // b3025040
+ NEG X5, X6 // 33035040
+ NEGW X5 // bb025040
+ NEGW X5, X6 // 3b035040
+
// These jumps can get printed as jumps to 2 because they go to the
// second instruction in the function (the first instruction is an
// invisible stack pointer adjustment).
- JMP start // JMP 2 // 6ff01fc6
+ JMP start // JMP 2 // 6ff01fc5
JMP (X5) // 67800200
JMP 4(X5) // 67804200
diff --git a/src/cmd/internal/obj/riscv/anames.go b/src/cmd/internal/obj/riscv/anames.go
index 9edf8f0..fa236d8 100644
--- a/src/cmd/internal/obj/riscv/anames.go
+++ b/src/cmd/internal/obj/riscv/anames.go
@@ -239,6 +239,8 @@
"MOVHU",
"MOVW",
"MOVWU",
+ "NEG",
+ "NEGW",
"NOT",
"SEQZ",
"SNEZ",
diff --git a/src/cmd/internal/obj/riscv/cpu.go b/src/cmd/internal/obj/riscv/cpu.go
index c1fc67f..632b3e6 100644
--- a/src/cmd/internal/obj/riscv/cpu.go
+++ b/src/cmd/internal/obj/riscv/cpu.go
@@ -589,6 +589,8 @@
AMOVHU
AMOVW
AMOVWU
+ ANEG
+ ANEGW
ANOT
ASEQZ
ASNEZ
diff --git a/src/cmd/internal/obj/riscv/obj.go b/src/cmd/internal/obj/riscv/obj.go
index e003584..ed5d533 100644
--- a/src/cmd/internal/obj/riscv/obj.go
+++ b/src/cmd/internal/obj/riscv/obj.go
@@ -1849,6 +1849,17 @@
ins.rs1 = uint32(p.From.Reg)
ins.rs2 = REG_F0
+ case ANEG, ANEGW:
+ // NEG rs, rd -> SUB rs, X0, rd
+ ins.as = ASUB
+ if p.As == ANEGW {
+ ins.as = ASUBW
+ }
+ ins.rs1 = REG_ZERO
+ if ins.rd == obj.REG_NONE {
+ ins.rd = ins.rs2
+ }
+
case ANOT:
// NOT rs, rd -> XORI $-1, rs, rd
ins.as = AXORI
