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[Qemu-devel] [6518] soft-float: add float32_log2() and float64_log2()
From: |
Aurelien Jarno |
Subject: |
[Qemu-devel] [6518] soft-float: add float32_log2() and float64_log2() |
Date: |
Thu, 05 Feb 2009 13:42:47 +0000 |
Revision: 6518
http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=6518
Author: aurel32
Date: 2009-02-05 13:42:47 +0000 (Thu, 05 Feb 2009)
Log Message:
-----------
soft-float: add float32_log2() and float64_log2()
Signed-off-by: Aurelien Jarno <address@hidden>
Modified Paths:
--------------
trunk/fpu/softfloat.c
trunk/fpu/softfloat.h
Modified: trunk/fpu/softfloat.c
===================================================================
--- trunk/fpu/softfloat.c 2009-02-04 20:39:09 UTC (rev 6517)
+++ trunk/fpu/softfloat.c 2009-02-05 13:42:47 UTC (rev 6518)
@@ -2057,6 +2057,53 @@
}
/*----------------------------------------------------------------------------
+| Returns the binary log of the single-precision floating-point value `a'.
+| The operation is performed according to the IEC/IEEE Standard for Binary
+| Floating-Point Arithmetic.
+*----------------------------------------------------------------------------*/
+float32 float32_log2( float32 a STATUS_PARAM )
+{
+ flag aSign, zSign;
+ int16 aExp;
+ bits32 aSig, zSig, i;
+
+ aSig = extractFloat32Frac( a );
+ aExp = extractFloat32Exp( a );
+ aSign = extractFloat32Sign( a );
+
+ if ( aExp == 0 ) {
+ if ( aSig == 0 ) return packFloat32( 1, 0xFF, 0 );
+ normalizeFloat32Subnormal( aSig, &aExp, &aSig );
+ }
+ if ( aSign ) {
+ float_raise( float_flag_invalid STATUS_VAR);
+ return float32_default_nan;
+ }
+ if ( aExp == 0xFF ) {
+ if ( aSig ) return propagateFloat32NaN( a, float32_zero STATUS_VAR );
+ return a;
+ }
+
+ aExp -= 0x7F;
+ aSig |= 0x00800000;
+ zSign = aExp < 0;
+ zSig = aExp << 23;
+
+ for (i = 1 << 22; i > 0; i >>= 1) {
+ aSig = ( (bits64)aSig * aSig ) >> 23;
+ if ( aSig & 0x01000000 ) {
+ aSig >>= 1;
+ zSig |= i;
+ }
+ }
+
+ if ( zSign )
+ zSig = -zSig;
+
+ return normalizeRoundAndPackFloat32( zSign, 0x85, zSig STATUS_VAR );
+}
+
+/*----------------------------------------------------------------------------
| Returns 1 if the single-precision floating-point value `a' is equal to
| the corresponding value `b', and 0 otherwise. The comparison is performed
| according to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.
@@ -3006,6 +3053,52 @@
}
/*----------------------------------------------------------------------------
+| Returns the binary log of the double-precision floating-point value `a'.
+| The operation is performed according to the IEC/IEEE Standard for Binary
+| Floating-Point Arithmetic.
+*----------------------------------------------------------------------------*/
+float64 float64_log2( float64 a STATUS_PARAM )
+{
+ flag aSign, zSign;
+ int16 aExp;
+ bits64 aSig, aSig0, aSig1, zSig, i;
+
+ aSig = extractFloat64Frac( a );
+ aExp = extractFloat64Exp( a );
+ aSign = extractFloat64Sign( a );
+
+ if ( aExp == 0 ) {
+ if ( aSig == 0 ) return packFloat64( 1, 0x7FF, 0 );
+ normalizeFloat64Subnormal( aSig, &aExp, &aSig );
+ }
+ if ( aSign ) {
+ float_raise( float_flag_invalid STATUS_VAR);
+ return float64_default_nan;
+ }
+ if ( aExp == 0x7FF ) {
+ if ( aSig ) return propagateFloat64NaN( a, float64_zero STATUS_VAR );
+ return a;
+ }
+
+ aExp -= 0x3FF;
+ aSig |= LIT64( 0x0010000000000000 );
+ zSign = aExp < 0;
+ zSig = (bits64)aExp << 52;
+ for (i = 1LL << 51; i > 0; i >>= 1) {
+ mul64To128( aSig, aSig, &aSig0, &aSig1 );
+ aSig = ( aSig0 << 12 ) | ( aSig1 >> 52 );
+ if ( aSig & LIT64( 0x0020000000000000 ) ) {
+ aSig >>= 1;
+ zSig |= i;
+ }
+ }
+
+ if ( zSign )
+ zSig = -zSig;
+ return normalizeRoundAndPackFloat64( zSign, 0x408, zSig STATUS_VAR );
+}
+
+/*----------------------------------------------------------------------------
| Returns 1 if the double-precision floating-point value `a' is equal to the
| corresponding value `b', and 0 otherwise. The comparison is performed
| according to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.
Modified: trunk/fpu/softfloat.h
===================================================================
--- trunk/fpu/softfloat.h 2009-02-04 20:39:09 UTC (rev 6517)
+++ trunk/fpu/softfloat.h 2009-02-05 13:42:47 UTC (rev 6518)
@@ -269,6 +269,7 @@
float32 float32_div( float32, float32 STATUS_PARAM );
float32 float32_rem( float32, float32 STATUS_PARAM );
float32 float32_sqrt( float32 STATUS_PARAM );
+float32 float32_log2( float32 STATUS_PARAM );
int float32_eq( float32, float32 STATUS_PARAM );
int float32_le( float32, float32 STATUS_PARAM );
int float32_lt( float32, float32 STATUS_PARAM );
@@ -339,6 +340,7 @@
float64 float64_div( float64, float64 STATUS_PARAM );
float64 float64_rem( float64, float64 STATUS_PARAM );
float64 float64_sqrt( float64 STATUS_PARAM );
+float64 float64_log2( float64 STATUS_PARAM );
int float64_eq( float64, float64 STATUS_PARAM );
int float64_le( float64, float64 STATUS_PARAM );
int float64_lt( float64, float64 STATUS_PARAM );
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Aurelien Jarno <=