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[RFC PATCH 1/8] softfloat: Use mulu64 for mul64To128
From: |
Alex Bennée |
Subject: |
[RFC PATCH 1/8] softfloat: Use mulu64 for mul64To128 |
Date: |
Tue, 20 Oct 2020 17:37:31 +0100 |
From: Richard Henderson <richard.henderson@linaro.org>
Via host-utils.h, we use a host widening multiply for
64-bit hosts, and a common subroutine for 32-bit hosts.
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200925152047.709901-2-richard.henderson@linaro.org>
---
include/fpu/softfloat-macros.h | 24 ++++--------------------
1 file changed, 4 insertions(+), 20 deletions(-)
diff --git a/include/fpu/softfloat-macros.h b/include/fpu/softfloat-macros.h
index a35ec2893a..57845f8af0 100644
--- a/include/fpu/softfloat-macros.h
+++ b/include/fpu/softfloat-macros.h
@@ -83,6 +83,7 @@ this code that are retained.
#define FPU_SOFTFLOAT_MACROS_H
#include "fpu/softfloat-types.h"
+#include "qemu/host-utils.h"
/*----------------------------------------------------------------------------
| Shifts `a' right by the number of bits given in `count'. If any nonzero
@@ -515,27 +516,10 @@ static inline void
| `z0Ptr' and `z1Ptr'.
*----------------------------------------------------------------------------*/
-static inline void mul64To128( uint64_t a, uint64_t b, uint64_t *z0Ptr,
uint64_t *z1Ptr )
+static inline void
+mul64To128(uint64_t a, uint64_t b, uint64_t *z0Ptr, uint64_t *z1Ptr)
{
- uint32_t aHigh, aLow, bHigh, bLow;
- uint64_t z0, zMiddleA, zMiddleB, z1;
-
- aLow = a;
- aHigh = a>>32;
- bLow = b;
- bHigh = b>>32;
- z1 = ( (uint64_t) aLow ) * bLow;
- zMiddleA = ( (uint64_t) aLow ) * bHigh;
- zMiddleB = ( (uint64_t) aHigh ) * bLow;
- z0 = ( (uint64_t) aHigh ) * bHigh;
- zMiddleA += zMiddleB;
- z0 += ( ( (uint64_t) ( zMiddleA < zMiddleB ) )<<32 ) + ( zMiddleA>>32 );
- zMiddleA <<= 32;
- z1 += zMiddleA;
- z0 += ( z1 < zMiddleA );
- *z1Ptr = z1;
- *z0Ptr = z0;
-
+ mulu64(z1Ptr, z0Ptr, a, b);
}
/*----------------------------------------------------------------------------
--
2.20.1
- [RFC PATCH 0/8] fpu: experimental conversion of float128_addsub, Alex Bennée, 2020/10/20
- [RFC PATCH 1/8] softfloat: Use mulu64 for mul64To128,
Alex Bennée <=
- [RFC PATCH 2/8] softfloat: Use int128.h for some operations, Alex Bennée, 2020/10/20
- [RFC PATCH 3/8] softfloat: Tidy a * b + inf return, Alex Bennée, 2020/10/20
- [RFC PATCH 4/8] softfloat: Add float_cmask and constants, Alex Bennée, 2020/10/20
- [RFC PATCH 7/8] tests/fp: add quad support to the benchmark utility, Alex Bennée, 2020/10/20
- [RFC PATCH 6/8] int128.h: add bunch of uint128 utility functions (INCOMPLETE), Alex Bennée, 2020/10/20
- [RFC PATCH 8/8] softfloat: implement addsub_floats128 using Uint128 and new style code, Alex Bennée, 2020/10/20
- [RFC PATCH 5/8] softfloat: Inline pick_nan_muladd into its caller, Alex Bennée, 2020/10/20
- Re: [RFC PATCH 0/8] fpu: experimental conversion of float128_addsub, no-reply, 2020/10/20