All of lore.kernel.org
 help / color / mirror / Atom feed
From: Richard Henderson <richard.henderson@linaro.org>
To: qemu-devel@nongnu.org
Cc: alex.bennee@linaro.org, david@redhat.com
Subject: [PATCH v2 09/28] softfloat: Reduce FloatFmt
Date: Tue, 25 May 2021 08:06:47 -0700	[thread overview]
Message-ID: <20210525150706.294968-10-richard.henderson@linaro.org> (raw)
In-Reply-To: <20210525150706.294968-1-richard.henderson@linaro.org>

Remove frac_lsb, frac_lsbm1, roundeven_mask.  Compute
these from round_mask in parts$N_uncanon_normal.

With floatx80, round_mask will not be tied to frac_shift.
Everything else is easily computable.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 fpu/softfloat.c           | 29 ++++++++++++-----------------
 fpu/softfloat-parts.c.inc |  6 +++---
 2 files changed, 15 insertions(+), 20 deletions(-)

diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 2f2bea84da..f6adc2c5ec 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -563,9 +563,7 @@ typedef struct {
  *   frac_size: the size of the fraction field
  *   frac_shift: shift to normalise the fraction with DECOMPOSED_BINARY_POINT
  * The following are computed based the size of fraction
- *   frac_lsb: least significant bit of fraction
- *   frac_lsbm1: the bit below the least significant bit (for rounding)
- *   round_mask/roundeven_mask: masks used for rounding
+ *   round_mask: bits below lsb which must be rounded
  * The following optional modifiers are available:
  *   arm_althp: handle ARM Alternative Half Precision
  */
@@ -575,24 +573,21 @@ typedef struct {
     int exp_max;
     int frac_size;
     int frac_shift;
-    uint64_t frac_lsb;
-    uint64_t frac_lsbm1;
-    uint64_t round_mask;
-    uint64_t roundeven_mask;
     bool arm_althp;
+    uint64_t round_mask;
 } FloatFmt;
 
 /* Expand fields based on the size of exponent and fraction */
-#define FLOAT_PARAMS(E, F)                                           \
-    .exp_size       = E,                                             \
-    .exp_bias       = ((1 << E) - 1) >> 1,                           \
-    .exp_max        = (1 << E) - 1,                                  \
-    .frac_size      = F,                                             \
-    .frac_shift     = (-F - 1) & 63,                                 \
-    .frac_lsb       = 1ull << ((-F - 1) & 63),                       \
-    .frac_lsbm1     = 1ull << ((-F - 2) & 63),                       \
-    .round_mask     = (1ull << ((-F - 1) & 63)) - 1,                 \
-    .roundeven_mask = (2ull << ((-F - 1) & 63)) - 1
+#define FLOAT_PARAMS_(E, F)                             \
+    .exp_size       = E,                                \
+    .exp_bias       = ((1 << E) - 1) >> 1,              \
+    .exp_max        = (1 << E) - 1,                     \
+    .frac_size      = F
+
+#define FLOAT_PARAMS(E, F)                              \
+    FLOAT_PARAMS_(E, F),                                \
+    .frac_shift     = (-F - 1) & 63,                    \
+    .round_mask     = (1ull << ((-F - 1) & 63)) - 1
 
 static const FloatFmt float16_params = {
     FLOAT_PARAMS(5, 10)
diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
index d72fe3ab08..b456c1c30c 100644
--- a/fpu/softfloat-parts.c.inc
+++ b/fpu/softfloat-parts.c.inc
@@ -145,10 +145,10 @@ static void partsN(uncanon_normal)(FloatPartsN *p, float_status *s,
 {
     const int exp_max = fmt->exp_max;
     const int frac_shift = fmt->frac_shift;
-    const uint64_t frac_lsb = fmt->frac_lsb;
-    const uint64_t frac_lsbm1 = fmt->frac_lsbm1;
     const uint64_t round_mask = fmt->round_mask;
-    const uint64_t roundeven_mask = fmt->roundeven_mask;
+    const uint64_t frac_lsb = round_mask + 1;
+    const uint64_t frac_lsbm1 = round_mask ^ (round_mask >> 1);
+    const uint64_t roundeven_mask = round_mask | frac_lsb;
     uint64_t inc;
     bool overflow_norm;
     int exp, flags = 0;
-- 
2.25.1



  parent reply	other threads:[~2021-05-25 16:11 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-25 15:06 [PATCH v2 00/28] Convert floatx80 and float128 to FloatParts Richard Henderson
2021-05-25 15:06 ` [PATCH v2 01/28] softfloat: Move round_to_uint_and_pack to softfloat-parts.c.inc Richard Henderson
2021-06-02 11:12   ` Alex Bennée
2021-05-25 15:06 ` [PATCH v2 02/28] softfloat: Move int_to_float " Richard Henderson
2021-05-26 13:34   ` David Hildenbrand
2021-06-02 11:14   ` Alex Bennée
2021-05-25 15:06 ` [PATCH v2 03/28] softfloat: Move uint_to_float " Richard Henderson
2021-05-26 13:36   ` David Hildenbrand
2021-06-02 11:31   ` Alex Bennée
2021-06-02 16:28     ` Richard Henderson
2021-05-25 15:06 ` [PATCH v2 04/28] softfloat: Move minmax_flags " Richard Henderson
2021-05-26 13:45   ` David Hildenbrand
2021-06-02 20:36   ` Alex Bennée
2021-06-02 22:23     ` Richard Henderson
2021-06-02 22:29   ` Richard Henderson
2021-05-25 15:06 ` [PATCH v2 05/28] softfloat: Move compare_floats " Richard Henderson
2021-06-03  9:00   ` Alex Bennée
2021-05-25 15:06 ` [PATCH v2 06/28] softfloat: Move scalbn_decomposed " Richard Henderson
2021-06-03  9:01   ` Alex Bennée
2021-05-25 15:06 ` [PATCH v2 07/28] softfloat: Move sqrt_float " Richard Henderson
2021-06-03  9:17   ` Alex Bennée
2021-05-25 15:06 ` [PATCH v2 08/28] softfloat: Split out parts_uncanon_normal Richard Henderson
2021-06-03  9:22   ` Alex Bennée
2021-05-25 15:06 ` Richard Henderson [this message]
2021-06-03  9:23   ` [PATCH v2 09/28] softfloat: Reduce FloatFmt Alex Bennée
2021-05-25 15:06 ` [PATCH v2 10/28] softfloat: Introduce Floatx80RoundPrec Richard Henderson
2021-06-03  9:26   ` Alex Bennée
2021-05-25 15:06 ` [PATCH v2 11/28] softfloat: Adjust parts_uncanon_normal for floatx80 Richard Henderson
2021-06-03 11:58   ` Alex Bennée
2021-05-25 15:06 ` [PATCH v2 12/28] tests/fp/fp-test: Reverse order of floatx80 precision tests Richard Henderson
2021-05-25 15:06 ` [PATCH v2 13/28] softfloat: Convert floatx80_add/sub to FloatParts Richard Henderson
2021-06-03 14:23   ` Alex Bennée
2021-05-25 15:06 ` [PATCH v2 14/28] softfloat: Convert floatx80_mul " Richard Henderson
2021-06-03 14:23   ` Alex Bennée
2021-05-25 15:06 ` [PATCH v2 15/28] softfloat: Convert floatx80_div " Richard Henderson
2021-06-03 14:23   ` Alex Bennée
2021-05-25 15:06 ` [PATCH v2 16/28] softfloat: Convert floatx80_sqrt " Richard Henderson
2021-06-03 14:24   ` Alex Bennée
2021-05-25 15:06 ` [PATCH v2 17/28] softfloat: Convert floatx80_round " Richard Henderson
2021-06-03 14:25   ` Alex Bennée
2021-05-25 15:06 ` [PATCH v2 18/28] softfloat: Convert floatx80_round_to_int " Richard Henderson
2021-06-03 14:26   ` Alex Bennée
2021-05-25 15:06 ` [PATCH v2 19/28] softfloat: Convert integer to floatx80 " Richard Henderson
2021-06-03 14:26   ` Alex Bennée
2021-05-25 15:06 ` [PATCH v2 20/28] softfloat: Convert floatx80 float conversions " Richard Henderson
2021-06-03 14:26   ` Alex Bennée
2021-05-25 15:06 ` [PATCH v2 21/28] softfloat: Convert floatx80 to integer " Richard Henderson
2021-06-03 14:27   ` Alex Bennée
2021-05-25 15:07 ` [PATCH v2 22/28] softfloat: Convert floatx80_scalbn " Richard Henderson
2021-06-03 14:34   ` Alex Bennée
2021-05-25 15:07 ` [PATCH v2 23/28] softfloat: Convert floatx80 compare " Richard Henderson
2021-06-03 14:34   ` Alex Bennée
2021-05-25 15:07 ` [PATCH v2 24/28] softfloat: Convert float32_exp2 " Richard Henderson
2021-06-03 14:44   ` Alex Bennée
2021-05-25 15:07 ` [PATCH v2 25/28] softfloat: Move floatN_log2 to softfloat-parts.c.inc Richard Henderson
2021-06-02 15:28   ` Alex Bennée
2021-05-25 15:07 ` [PATCH v2 26/28] softfloat: Convert modrem operations to FloatParts Richard Henderson
2021-06-03 14:48   ` Alex Bennée
2021-05-25 15:07 ` [PATCH v2 27/28] tests/fp: Enable more tests Richard Henderson
2021-05-25 15:07 ` [PATCH v2 28/28] softfloat: Use hard-float for {u}int64_to_float{32, 64} Richard Henderson
2021-06-03 14:57   ` [PATCH v2 28/28] softfloat: Use hard-float for {u}int64_to_float{32,64} Alex Bennée
2021-05-25 16:51 ` [PATCH v2 00/28] Convert floatx80 and float128 to FloatParts no-reply

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=20210525150706.294968-10-richard.henderson@linaro.org \
    --to=richard.henderson@linaro.org \
    --cc=alex.bennee@linaro.org \
    --cc=david@redhat.com \
    --cc=qemu-devel@nongnu.org \
    --subject='Re: [PATCH v2 09/28] softfloat: Reduce FloatFmt' \
    /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

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.