From: Richard Henderson <richard.henderson@linaro.org>
To: qemu-devel@nongnu.org
Cc: alex.bennee@linaro.org, David Hildenbrand <david@redhat.com>
Subject: [RFC PATCH 07/15] softfloat: Use int128.h for some operations
Date: Tue, 20 Oct 2020 21:51:41 -0700 [thread overview]
Message-ID: <20201021045149.1582203-8-richard.henderson@linaro.org> (raw)
In-Reply-To: <20201021045149.1582203-1-richard.henderson@linaro.org>
Use our Int128, which wraps the compiler's __int128_t, instead
of open-coding shifts and arithmetic. We'd need to extend Int128
to to replace more than these four.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
include/fpu/softfloat-macros.h | 65 ++++++++++++++--------------------
1 file changed, 26 insertions(+), 39 deletions(-)
diff --git a/include/fpu/softfloat-macros.h b/include/fpu/softfloat-macros.h
index 57845f8af0..e6f05c048e 100644
--- a/include/fpu/softfloat-macros.h
+++ b/include/fpu/softfloat-macros.h
@@ -84,6 +84,7 @@ this code that are retained.
#include "fpu/softfloat-types.h"
#include "qemu/host-utils.h"
+#include "qemu/int128.h"
/*----------------------------------------------------------------------------
| Shifts `a' right by the number of bits given in `count'. If any nonzero
@@ -191,28 +192,14 @@ static inline void
| which are stored at the locations pointed to by `z0Ptr' and `z1Ptr'.
*----------------------------------------------------------------------------*/
-static inline void
- shift128Right(
- uint64_t a0, uint64_t a1, int count, uint64_t *z0Ptr, uint64_t *z1Ptr)
+static inline void shift128Right(uint64_t a0, uint64_t a1, int count,
+ uint64_t *z0Ptr, uint64_t *z1Ptr)
{
- uint64_t z0, z1;
- int8_t negCount = ( - count ) & 63;
-
- if ( count == 0 ) {
- z1 = a1;
- z0 = a0;
- }
- else if ( count < 64 ) {
- z1 = ( a0<<negCount ) | ( a1>>count );
- z0 = a0>>count;
- }
- else {
- z1 = (count < 128) ? (a0 >> (count & 63)) : 0;
- z0 = 0;
- }
- *z1Ptr = z1;
- *z0Ptr = z0;
+ Int128 a = int128_make128(a1, a0);
+ Int128 z = int128_shr(a, count);
+ *z0Ptr = int128_gethi(z);
+ *z1Ptr = int128_getlo(z);
}
/*----------------------------------------------------------------------------
@@ -352,13 +339,11 @@ static inline void shortShift128Left(uint64_t a0, uint64_t a1, int count,
static inline void shift128Left(uint64_t a0, uint64_t a1, int count,
uint64_t *z0Ptr, uint64_t *z1Ptr)
{
- if (count < 64) {
- *z1Ptr = a1 << count;
- *z0Ptr = count == 0 ? a0 : (a0 << count) | (a1 >> (-count & 63));
- } else {
- *z1Ptr = 0;
- *z0Ptr = a1 << (count - 64);
- }
+ Int128 a = int128_make128(a1, a0);
+ Int128 z = int128_shl(a, count);
+
+ *z0Ptr = int128_gethi(z);
+ *z1Ptr = int128_getlo(z);
}
/*----------------------------------------------------------------------------
@@ -405,15 +390,15 @@ static inline void
*----------------------------------------------------------------------------*/
static inline void
- add128(
- uint64_t a0, uint64_t a1, uint64_t b0, uint64_t b1, uint64_t *z0Ptr, uint64_t *z1Ptr )
+add128(uint64_t a0, uint64_t a1, uint64_t b0, uint64_t b1,
+ uint64_t *z0Ptr, uint64_t *z1Ptr)
{
- uint64_t z1;
-
- z1 = a1 + b1;
- *z1Ptr = z1;
- *z0Ptr = a0 + b0 + ( z1 < a1 );
+ Int128 a = int128_make128(a1, a0);
+ Int128 b = int128_make128(b1, b0);
+ Int128 z = int128_add(a, b);
+ *z0Ptr = int128_gethi(z);
+ *z1Ptr = int128_getlo(z);
}
/*----------------------------------------------------------------------------
@@ -463,13 +448,15 @@ static inline void
*----------------------------------------------------------------------------*/
static inline void
- sub128(
- uint64_t a0, uint64_t a1, uint64_t b0, uint64_t b1, uint64_t *z0Ptr, uint64_t *z1Ptr )
+sub128(uint64_t a0, uint64_t a1, uint64_t b0, uint64_t b1,
+ uint64_t *z0Ptr, uint64_t *z1Ptr)
{
+ Int128 a = int128_make128(a1, a0);
+ Int128 b = int128_make128(b1, b0);
+ Int128 z = int128_sub(a, b);
- *z1Ptr = a1 - b1;
- *z0Ptr = a0 - b0 - ( a1 < b1 );
-
+ *z0Ptr = int128_gethi(z);
+ *z1Ptr = int128_getlo(z);
}
/*----------------------------------------------------------------------------
--
2.25.1
next prev parent reply other threads:[~2020-10-21 4:58 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-21 4:51 [RFC PATCH 00/15] softfloat: alternate conversion of float128_addsub Richard Henderson
2020-10-21 4:51 ` [RFC PATCH 01/15] qemu/int128: Add int128_or Richard Henderson
2020-10-21 17:13 ` Alex Bennée
2020-10-29 15:01 ` Taylor Simpson
2020-10-29 18:09 ` Philippe Mathieu-Daudé
2021-02-14 18:17 ` Philippe Mathieu-Daudé
2020-10-21 4:51 ` [RFC PATCH 02/15] qemu/int128: Add int128_clz, int128_ctz Richard Henderson
2020-10-21 17:13 ` Alex Bennée
2021-02-14 18:17 ` Philippe Mathieu-Daudé
2020-10-21 4:51 ` [RFC PATCH 03/15] qemu/int128: Rename int128_rshift, int128_lshift Richard Henderson
2020-10-21 17:14 ` Alex Bennée
2021-02-14 18:18 ` Philippe Mathieu-Daudé
2020-10-21 4:51 ` [RFC PATCH 04/15] qemu/int128: Add int128_shr Richard Henderson
2020-10-21 4:51 ` [RFC PATCH 05/15] qemu/int128: Add int128_geu Richard Henderson
2021-02-14 18:19 ` Philippe Mathieu-Daudé
2020-10-21 4:51 ` [RFC PATCH 06/15] softfloat: Use mulu64 for mul64To128 Richard Henderson
2020-10-21 4:51 ` Richard Henderson [this message]
2020-10-21 4:51 ` [RFC PATCH 08/15] softfloat: Tidy a * b + inf return Richard Henderson
2020-10-21 4:51 ` [RFC PATCH 09/15] softfloat: Add float_cmask and constants Richard Henderson
2020-10-21 4:51 ` [RFC PATCH 10/15] softfloat: Inline float_raise Richard Henderson
2020-10-21 17:16 ` Alex Bennée
2021-02-14 18:20 ` Philippe Mathieu-Daudé
2020-10-21 4:51 ` [RFC PATCH 11/15] Test split to softfloat-parts.c.inc Richard Henderson
2020-10-21 4:51 ` [RFC PATCH 12/15] softfloat: Streamline FloatFmt Richard Henderson
2020-10-21 4:51 ` [RFC PATCH 13/15] Test float128_addsub Richard Henderson
2020-10-21 4:51 ` [RFC PATCH 14/15] softfloat: Use float_cmask for addsub_floats Richard Henderson
2020-10-21 4:51 ` [RFC PATCH 15/15] softfloat: Improve subtraction of equal exponent Richard Henderson
2020-10-21 5:12 ` [RFC PATCH 00/15] softfloat: alternate conversion of float128_addsub no-reply
2020-10-21 17:46 ` Alex Bennée
2020-10-21 17:53 ` Richard Henderson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201021045149.1582203-8-richard.henderson@linaro.org \
--to=richard.henderson@linaro.org \
--cc=alex.bennee@linaro.org \
--cc=david@redhat.com \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.