Roger Chang has submitted this change. (
https://gem5-review.googlesource.com/c/public/gem5/+/70358?usp=email )
Change subject: arch-riscv: Refactor RVC decode flow when funct4==0b1001
and op==C2
......................................................................
arch-riscv: Refactor RVC decode flow when funct4==0b1001 and op==C2
the compressed instruction 0x901e (c.add zero, t2) should be decoded as
"c_add zero, t2" not c_ebreak
Change-Id: Ib2bd4b4d9739aa27ad290ead313e95b11b1727d1
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/70358
Reviewed-by: Jason Lowe-Power <power...@gmail.com>
Maintainer: Jason Lowe-Power <power...@gmail.com>
Tested-by: kokoro <noreply+kok...@google.com>
---
M src/arch/riscv/isa/decoder.isa
1 file changed, 11 insertions(+), 17 deletions(-)
Approvals:
Jason Lowe-Power: Looks good to me, approved; Looks good to me, approved
kokoro: Regressions pass
diff --git a/src/arch/riscv/isa/decoder.isa b/src/arch/riscv/isa/decoder.isa
index d89a0c9..f22efb0 100644
--- a/src/arch/riscv/isa/decoder.isa
+++ b/src/arch/riscv/isa/decoder.isa
@@ -365,27 +365,21 @@
Rc1 = rvSext(Rc2);
}});
}
- 0x1: decode RC1 {
- 0x0: SystemOp::c_ebreak({{
- if (RC2 != 0) {
- return std::make_shared<IllegalInstFault>(
- "source reg x1", machInst);
- }
- return
std::make_shared<BreakpointFault>(xc->pcState());
- }}, IsSerializeAfter, IsNonSpeculative, No_OpClass);
- default: decode RC2 {
- 0x0: Jump::c_jalr({{
- if (RC1 == 0) {
- return std::make_shared<IllegalInstFault>(
- "source reg x0", machInst);
- }
+ 0x1: decode RC2 {
+ 0x0: decode RC1 {
+ 0x0: SystemOp::c_ebreak({{
+ return std::make_shared<BreakpointFault>(
+ xc->pcState());
+ }}, IsSerializeAfter, IsNonSpeculative, No_OpClass);
+ default: Jump::c_jalr({{
ra = rvSext(NPC);
NPC = rvZext(Rc1);
}}, IsIndirectControl, IsUncondControl, IsCall);
- default: CompressedROp::c_add({{
- Rc1_sd = rvSext(Rc1_sd + Rc2_sd);
- }});
}
+ default: CompressedROp::c_add({{
+ // RC1 == 0 is HINT
+ Rc1_sd = rvSext(Rc1_sd + Rc2_sd);
+ }});
}
}
format CompressedStore {
--
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Gerrit-MessageType: merged
Gerrit-Project: public/gem5
Gerrit-Branch: develop
Gerrit-Change-Id: Ib2bd4b4d9739aa27ad290ead313e95b11b1727d1
Gerrit-Change-Number: 70358
Gerrit-PatchSet: 7
Gerrit-Owner: Roger Chang <rogerycch...@google.com>
Gerrit-Reviewer: Bobby Bruce <bbr...@ucdavis.edu>
Gerrit-Reviewer: Hoa Nguyen <hoangu...@ucdavis.edu>
Gerrit-Reviewer: Jason Lowe-Power <ja...@lowepower.com>
Gerrit-Reviewer: Jason Lowe-Power <power...@gmail.com>
Gerrit-Reviewer: Roger Chang <rogerycch...@google.com>
Gerrit-Reviewer: kokoro <noreply+kok...@google.com>
Gerrit-CC: Yu-hsin Wang <yuhsi...@google.com>
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