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arch-riscv: Fix unexpected behavior of float operations in Mac OS

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The uint_fast16_t is the integer at least 16 bits size, it can be
32, 64 bits and more. Usually most of the simulations are in the
x86-64 linux host, the size of uint_fast16_t is 64 bits. Therefore,
there is no problem for double precision float operations and it can
pass FloatMM test. However, in the Mac OS, the size of uint_fast16_t
is 16 bits, it will lose the upper bits when converting float
register bits to freg_t and it will generate unexpected results for
FloatMM test.

The change can guarantee that the size of data in freg_t is at least
64 bits and it will not lose any data from floating point to freg_t.

Reference:
https://developer.apple.com/documentation/kernel/uint_fast16_t

https://codebrowser.dev/glibc/glibc/stdlib/stdint.h.html

Change-Id: I3df6610f0903cdee0f56584d6cbdb51ac26c86c8
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/71578
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This commit is contained in:
Roger Chang
2023-06-13 17:25:47 +08:00
parent 28777e1114
commit 9a27322c7b
1 changed files with 1 additions and 1 deletions
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2
src/arch/riscv/regs/float.hh
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@@ -105,7 +105,7 @@ static constexpr float64_t f64(freg_t r) { return r; }
static constexpr freg_t freg(float16_t f) { return {boxF16(f.v)}; }
static constexpr freg_t freg(float32_t f) { return {boxF32(f.v)}; }
static constexpr freg_t freg(float64_t f) { return f; }
static constexpr freg_t freg(uint_fast16_t f) { return {f}; }
static constexpr freg_t freg(uint_fast64_t f) { return {f}; }
namespace float_reg
{