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authorRichard Henderson <richard.henderson@linaro.org>2020-11-20 18:28:31 -0800
committerRichard Henderson <richard.henderson@linaro.org>2021-06-03 14:04:02 -0700
commitd6e1f0cd59a59a27a2b109600653e57917cc9594 (patch)
tree3cb4ea079caa5333714b39206b0893fb370c6d2b /fpu/softfloat.c
parent25fdedf0d33e01ad4c950b7e4d58da498649aa29 (diff)
downloadfocaccia-qemu-d6e1f0cd59a59a27a2b109600653e57917cc9594.tar.gz
focaccia-qemu-d6e1f0cd59a59a27a2b109600653e57917cc9594.zip
softfloat: Reduce FloatFmt
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.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'fpu/softfloat.c')
-rw-r--r--fpu/softfloat.c29
1 files changed, 12 insertions, 17 deletions
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index ea7ee13201..741480c568 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)