Roger Chang has uploaded this change for review. (
https://gem5-review.googlesource.com/c/public/gem5/+/71479?usp=email )
Change subject: arch-riscv: Refactor fmax and fmin instructions
......................................................................
arch-riscv: Refactor fmax and fmin instructions
Currently fmax and fmin instructions convert source float registers such as
Fs1_bits to float64_t(or float32_t and float16_t) many times in the single
instruction. It is not efficient for the future maintenance of these
instructions.
The change adds non-register float_t intermediate variables fs1 and fs2 to
keep converted results so that we don’t need to do it repeatedly. It also
added an intermediate variable fd for specific float type to assume the
upper
bits of the packed float register are all one.
Change-Id: Ic508d5255db6c4b38ca4df6dd805df440c043fff
---
M src/arch/riscv/isa/decoder.isa
1 file changed, 54 insertions(+), 67 deletions(-)
diff --git a/src/arch/riscv/isa/decoder.isa b/src/arch/riscv/isa/decoder.isa
index 2dcd118..a339c11 100644
--- a/src/arch/riscv/isa/decoder.isa
+++ b/src/arch/riscv/isa/decoder.isa
@@ -1615,93 +1615,80 @@
}
0x14: decode ROUND_MODE {
0x0: fmin_s({{
- bool less = f32_lt_quiet(f32(freg(Fs1_bits)),
- f32(freg(Fs2_bits))) ||
- (f32_eq(f32(freg(Fs1_bits)),
- f32(freg(Fs2_bits))) &&
- bits(f32(freg(Fs1_bits)).v, 31));
+ float32_t fs1 = f32(freg(Fs1_bits));
+ float32_t fs2 = f32(freg(Fs2_bits));
+ float32_t fd;
+ bool less = f32_lt_quiet(fs1, fs2) ||
+ (f32_eq(fs1, fs2) && bits(fs1.v, 31));
- Fd_bits = less ||
- isNaNF32UI(f32(freg(Fs2_bits)).v) ?
- freg(Fs1_bits).v : freg(Fs2_bits).v;
- if (isNaNF32UI(f32(freg(Fs1_bits)).v) &&
- isNaNF32UI(f32(freg(Fs2_bits)).v))
- Fd_bits = f32(defaultNaNF32UI).v;
+ fd = less || isNaNF32UI(fs2.v) ? fs1 : fs2;
+ if (isNaNF32UI(fs1.v) && isNaNF32UI(fs2.v))
+ fd = f32(defaultNaNF32UI);
+ Fd_bits = freg(fd).v;
}}, FloatCmpOp);
0x1: fmax_s({{
- bool greater = f32_lt_quiet(f32(freg(Fs2_bits)),
- f32(freg(Fs1_bits))) ||
- (f32_eq(f32(freg(Fs2_bits)),
- f32(freg(Fs1_bits))) &&
- bits(f32(freg(Fs2_bits)).v, 31));
+ float32_t fs1 = f32(freg(Fs1_bits));
+ float32_t fs2 = f32(freg(Fs2_bits));
+ float32_t fd;
+ bool greater = f32_lt_quiet(fs2, fs1) ||
+ (f32_eq(fs2, fs1) && bits(fs2.v, 31));
- Fd_bits = greater ||
- isNaNF32UI(f32(freg(Fs2_bits)).v) ?
- freg(Fs1_bits).v : freg(Fs2_bits).v;
- if (isNaNF32UI(f32(freg(Fs1_bits)).v) &&
- isNaNF32UI(f32(freg(Fs2_bits)).v))
- Fd_bits = f32(defaultNaNF32UI).v;
+ fd = greater || isNaNF32UI(fs2.v) ? fs1: fs2;
+ if (isNaNF32UI(fs1.v) && isNaNF32UI(fs2.v))
+ fd = f32(defaultNaNF32UI);
+ Fd_bits = freg(fd).v;
}}, FloatCmpOp);
}
0x15: decode ROUND_MODE {
0x0: fmin_d({{
- bool less = f64_lt_quiet(f64(freg(Fs1_bits)),
- f64(freg(Fs2_bits))) ||
- (f64_eq(f64(freg(Fs1_bits)),
- f64(freg(Fs2_bits))) &&
- bits(f64(freg(Fs1_bits)).v, 63));
+ float64_t fs1 = f64(freg(Fs1_bits));
+ float64_t fs2 = f64(freg(Fs2_bits));
+ float64_t fd;
+ bool less = f64_lt_quiet(fs1, fs2) ||
+ (f64_eq(fs1, fs2) && bits(fs1.v, 63));
- Fd_bits = less ||
- isNaNF64UI(f64(freg(Fs2_bits)).v) ?
- freg(Fs1_bits).v : freg(Fs2_bits).v;
- if (isNaNF64UI(f64(freg(Fs1_bits)).v) &&
- isNaNF64UI(f64(freg(Fs2_bits)).v))
- Fd_bits = f64(defaultNaNF64UI).v;
+ fd = less || isNaNF64UI(fs2.v) ? fs1 : fs2;
+ if (isNaNF64UI(fs1.v) && isNaNF64UI(fs2.v))
+ fd = f64(defaultNaNF64UI);
+ Fd_bits = freg(fd).v;
}}, FloatCmpOp);
0x1: fmax_d({{
- bool greater =
- f64_lt_quiet(f64(freg(Fs2_bits)),
- f64(freg(Fs1_bits))) ||
- (f64_eq(f64(freg(Fs2_bits)),
- f64(freg(Fs1_bits))) &&
- bits(f64(freg(Fs2_bits)).v, 63));
+ float64_t fs1 = f64(freg(Fs1_bits));
+ float64_t fs2 = f64(freg(Fs2_bits));
+ float64_t fd;
+ bool greater = f64_lt_quiet(fs2, fs1) ||
+ (f64_eq(fs2, fs1) && bits(fs2.v, 63));
- Fd_bits = greater ||
- isNaNF64UI(f64(freg(Fs2_bits)).v) ?
- freg(Fs1_bits).v : freg(Fs2_bits).v;
- if (isNaNF64UI(f64(freg(Fs1_bits)).v) &&
- isNaNF64UI(f64(Fs2_bits).v))
- Fd_bits = f64(defaultNaNF64UI).v;
+ fd = greater || isNaNF64UI(fs2.v) ? fs1 : fs2;
+ if (isNaNF64UI(fs1.v) && isNaNF64UI(fs2.v))
+ fd = f64(defaultNaNF64UI);
+ Fd_bits = freg(fd).v;
}}, FloatCmpOp);
}
0x16: decode ROUND_MODE {
0x0: fmin_h({{
- bool less = f16_lt_quiet(f16(freg(Fs1_bits)),
- f16(freg(Fs2_bits))) ||
- (f16_eq(f16(freg(Fs1_bits)),
- f16(freg(Fs2_bits))) &&
- bits(f16(freg(Fs1_bits)).v, 15));
+ float16_t fs1 = f16(freg(Fs1_bits));
+ float16_t fs2 = f16(freg(Fs2_bits));
+ float16_t fd;
+ bool less = f16_lt_quiet(fs1, fs2) ||
+ (f16_eq(fs1, fs2) && bits(fs1.v, 15));
- Fd_bits = less ||
- isNaNF16UI(f16(freg(Fs2_bits)).v) ?
- freg(Fs1_bits).v : freg(Fs2_bits).v;
- if (isNaNF16UI(f16(freg(Fs1_bits)).v) &&
- isNaNF16UI(f16(freg(Fs2_bits)).v))
- Fd_bits = f16(defaultNaNF16UI).v;
+ fd = less || isNaNF16UI(fs2.v) ? fs1 : fs2;
+ if (isNaNF16UI(fs1.v) && isNaNF16UI(fs2.v))
+ fd = f16(defaultNaNF16UI);
+ Fd_bits = freg(fd).v;
}}, FloatCmpOp);
0x1: fmax_h({{
- bool greater = f16_lt_quiet(f16(freg(Fs2_bits)),
- f16(freg(Fs1_bits))) ||
- (f16_eq(f16(freg(Fs2_bits)),
- f16(freg(Fs1_bits))) &&
- bits(f16(freg(Fs2_bits)).v, 15));
+ float16_t fs1 = f16(freg(Fs1_bits));
+ float16_t fs2 = f16(freg(Fs2_bits));
+ float16_t fd;
+ bool greater = f16_lt_quiet(fs2, fs1) ||
+ (f16_eq(fs2, fs1) && bits(fs2.v, 15));
- Fd_bits = greater ||
- isNaNF16UI(f16(freg(Fs2_bits)).v) ?
- freg(Fs1_bits).v : freg(Fs2_bits).v;
- if (isNaNF16UI(f16(freg(Fs1_bits)).v) &&
- isNaNF16UI(f16(freg(Fs2_bits)).v))
- Fd_bits = f16(defaultNaNF16UI).v;
+ fd = greater || isNaNF16UI(fs2.v) ? fs1 : fs2;
+ if (isNaNF16UI(fs1.v) && isNaNF16UI(fs2.v))
+ fd = f16(defaultNaNF16UI);
+ Fd_bits = freg(fd).v;
}}, FloatCmpOp);
}
0x20: decode CONV_SGN {
--
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Gerrit-MessageType: newchange
Gerrit-Project: public/gem5
Gerrit-Branch: develop
Gerrit-Change-Id: Ic508d5255db6c4b38ca4df6dd805df440c043fff
Gerrit-Change-Number: 71479
Gerrit-PatchSet: 1
Gerrit-Owner: Roger Chang <rogerycch...@google.com>
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