ksco has submitted this change. (
https://gem5-review.googlesource.com/c/public/gem5/+/57069 )
Change subject: arch-riscv: Fix a typo in fsgnjn_s decoder
......................................................................
arch-riscv: Fix a typo in fsgnjn_s decoder
Negating the register value before unboxing to float32 will
generally result in a canonical 32-bit NaN (without the sign
bit set) so the result was incorrect in many cases.
Change-Id: I0c1bb3aadfca135ab0cc5ba1b58fc83d71fd300c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/57069
Reviewed-by: Alex Richardson <[email protected]>
Reviewed-by: Gabe Black <[email protected]>
Maintainer: Gabe Black <[email protected]>
Reviewed-by: Luming Wang <[email protected]>
Tested-by: kokoro <[email protected]>
---
M src/arch/riscv/isa/decoder.isa
1 file changed, 29 insertions(+), 7 deletions(-)
Approvals:
Gabe Black: Looks good to me, approved; Looks good to me, approved
Luming Wang: Looks good to me, approved
Alex Richardson: Looks good to me, but someone else must approve
kokoro: Regressions pass
diff --git a/src/arch/riscv/isa/decoder.isa b/src/arch/riscv/isa/decoder.isa
index e512e08..c109d96 100644
--- a/src/arch/riscv/isa/decoder.isa
+++ b/src/arch/riscv/isa/decoder.isa
@@ -1025,17 +1025,20 @@
}}, FloatDivOp);
0x10: decode ROUND_MODE {
0x0: fsgnj_s({{
- Fd_bits = boxF32(insertBits(unboxF32(Fs2_bits),
30, 0,
- unboxF32(Fs1_bits)));
+ auto sign = bits(unboxF32(Fs2_bits), 31);
+ Fd_bits = boxF32(insertBits(unboxF32(Fs1_bits), 31,
+ sign));
}}, FloatMiscOp);
0x1: fsgnjn_s({{
- Fd_bits = boxF32(insertBits(unboxF32(~Fs2_bits),
30, 0,
- unboxF32(Fs1_bits)));
+ auto sign = ~bits(unboxF32(Fs2_bits), 31);
+ Fd_bits = boxF32(insertBits(unboxF32(Fs1_bits), 31,
+ sign));
}}, FloatMiscOp);
0x2: fsgnjx_s({{
- Fd_bits = boxF32(insertBits(
- unboxF32(Fs1_bits) ^
unboxF32(Fs2_bits),
- 30, 0, unboxF32(Fs1_bits)));
+ auto sign = bits(
+ unboxF32(Fs1_bits) ^ unboxF32(Fs2_bits), 31);
+ Fd_bits = boxF32(insertBits(unboxF32(Fs1_bits), 31,
+ sign));
}}, FloatMiscOp);
}
0x11: decode ROUND_MODE {
--
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Gerrit-Project: public/gem5
Gerrit-Branch: develop
Gerrit-Change-Id: I0c1bb3aadfca135ab0cc5ba1b58fc83d71fd300c
Gerrit-Change-Number: 57069
Gerrit-PatchSet: 3
Gerrit-Owner: ksco <[email protected]>
Gerrit-Reviewer: Alex Richardson <[email protected]>
Gerrit-Reviewer: Gabe Black <[email protected]>
Gerrit-Reviewer: Luming Wang <[email protected]>
Gerrit-Reviewer: kokoro <[email protected]>
Gerrit-Reviewer: ksco <[email protected]>
Gerrit-MessageType: merged
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