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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm26/nwfpe/fpa11_cprt.c
downloadlinux-stericsson-2.6.12-rc2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/arm26/nwfpe/fpa11_cprt.c')
-rw-r--r--arch/arm26/nwfpe/fpa11_cprt.c289
1 files changed, 289 insertions, 0 deletions
diff --git a/arch/arm26/nwfpe/fpa11_cprt.c b/arch/arm26/nwfpe/fpa11_cprt.c
new file mode 100644
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+++ b/arch/arm26/nwfpe/fpa11_cprt.c
@@ -0,0 +1,289 @@
+/*
+ NetWinder Floating Point Emulator
+ (c) Rebel.COM, 1998,1999
+ (c) Philip Blundell, 1999
+
+ Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "fpa11.h"
+#include "milieu.h"
+#include "softfloat.h"
+#include "fpopcode.h"
+#include "fpa11.inl"
+#include "fpmodule.h"
+#include "fpmodule.inl"
+
+extern flag floatx80_is_nan(floatx80);
+extern flag float64_is_nan( float64);
+extern flag float32_is_nan( float32);
+
+void SetRoundingMode(const unsigned int opcode);
+
+unsigned int PerformFLT(const unsigned int opcode);
+unsigned int PerformFIX(const unsigned int opcode);
+
+static unsigned int
+PerformComparison(const unsigned int opcode);
+
+unsigned int EmulateCPRT(const unsigned int opcode)
+{
+ unsigned int nRc = 1;
+
+ //printk("EmulateCPRT(0x%08x)\n",opcode);
+
+ if (opcode & 0x800000)
+ {
+ /* This is some variant of a comparison (PerformComparison will
+ sort out which one). Since most of the other CPRT
+ instructions are oddball cases of some sort or other it makes
+ sense to pull this out into a fast path. */
+ return PerformComparison(opcode);
+ }
+
+ /* Hint to GCC that we'd like a jump table rather than a load of CMPs */
+ switch ((opcode & 0x700000) >> 20)
+ {
+ case FLT_CODE >> 20: nRc = PerformFLT(opcode); break;
+ case FIX_CODE >> 20: nRc = PerformFIX(opcode); break;
+
+ case WFS_CODE >> 20: writeFPSR(readRegister(getRd(opcode))); break;
+ case RFS_CODE >> 20: writeRegister(getRd(opcode),readFPSR()); break;
+
+#if 0 /* We currently have no use for the FPCR, so there's no point
+ in emulating it. */
+ case WFC_CODE >> 20: writeFPCR(readRegister(getRd(opcode)));
+ case RFC_CODE >> 20: writeRegister(getRd(opcode),readFPCR()); break;
+#endif
+
+ default: nRc = 0;
+ }
+
+ return nRc;
+}
+
+unsigned int PerformFLT(const unsigned int opcode)
+{
+ FPA11 *fpa11 = GET_FPA11();
+
+ unsigned int nRc = 1;
+ SetRoundingMode(opcode);
+
+ switch (opcode & MASK_ROUNDING_PRECISION)
+ {
+ case ROUND_SINGLE:
+ {
+ fpa11->fType[getFn(opcode)] = typeSingle;
+ fpa11->fpreg[getFn(opcode)].fSingle =
+ int32_to_float32(readRegister(getRd(opcode)));
+ }
+ break;
+
+ case ROUND_DOUBLE:
+ {
+ fpa11->fType[getFn(opcode)] = typeDouble;
+ fpa11->fpreg[getFn(opcode)].fDouble =
+ int32_to_float64(readRegister(getRd(opcode)));
+ }
+ break;
+
+ case ROUND_EXTENDED:
+ {
+ fpa11->fType[getFn(opcode)] = typeExtended;
+ fpa11->fpreg[getFn(opcode)].fExtended =
+ int32_to_floatx80(readRegister(getRd(opcode)));
+ }
+ break;
+
+ default: nRc = 0;
+ }
+
+ return nRc;
+}
+
+unsigned int PerformFIX(const unsigned int opcode)
+{
+ FPA11 *fpa11 = GET_FPA11();
+ unsigned int nRc = 1;
+ unsigned int Fn = getFm(opcode);
+
+ SetRoundingMode(opcode);
+
+ switch (fpa11->fType[Fn])
+ {
+ case typeSingle:
+ {
+ writeRegister(getRd(opcode),
+ float32_to_int32(fpa11->fpreg[Fn].fSingle));
+ }
+ break;
+
+ case typeDouble:
+ {
+ writeRegister(getRd(opcode),
+ float64_to_int32(fpa11->fpreg[Fn].fDouble));
+ }
+ break;
+
+ case typeExtended:
+ {
+ writeRegister(getRd(opcode),
+ floatx80_to_int32(fpa11->fpreg[Fn].fExtended));
+ }
+ break;
+
+ default: nRc = 0;
+ }
+
+ return nRc;
+}
+
+
+static unsigned int __inline__
+PerformComparisonOperation(floatx80 Fn, floatx80 Fm)
+{
+ unsigned int flags = 0;
+
+ /* test for less than condition */
+ if (floatx80_lt(Fn,Fm))
+ {
+ flags |= CC_NEGATIVE;
+ }
+
+ /* test for equal condition */
+ if (floatx80_eq(Fn,Fm))
+ {
+ flags |= CC_ZERO;
+ }
+
+ /* test for greater than or equal condition */
+ if (floatx80_lt(Fm,Fn))
+ {
+ flags |= CC_CARRY;
+ }
+
+ writeConditionCodes(flags);
+ return 1;
+}
+
+/* This instruction sets the flags N, Z, C, V in the FPSR. */
+
+static unsigned int PerformComparison(const unsigned int opcode)
+{
+ FPA11 *fpa11 = GET_FPA11();
+ unsigned int Fn, Fm;
+ floatx80 rFn, rFm;
+ int e_flag = opcode & 0x400000; /* 1 if CxFE */
+ int n_flag = opcode & 0x200000; /* 1 if CNxx */
+ unsigned int flags = 0;
+
+ //printk("PerformComparison(0x%08x)\n",opcode);
+
+ Fn = getFn(opcode);
+ Fm = getFm(opcode);
+
+ /* Check for unordered condition and convert all operands to 80-bit
+ format.
+ ?? Might be some mileage in avoiding this conversion if possible.
+ Eg, if both operands are 32-bit, detect this and do a 32-bit
+ comparison (cheaper than an 80-bit one). */
+ switch (fpa11->fType[Fn])
+ {
+ case typeSingle:
+ //printk("single.\n");
+ if (float32_is_nan(fpa11->fpreg[Fn].fSingle))
+ goto unordered;
+ rFn = float32_to_floatx80(fpa11->fpreg[Fn].fSingle);
+ break;
+
+ case typeDouble:
+ //printk("double.\n");
+ if (float64_is_nan(fpa11->fpreg[Fn].fDouble))
+ goto unordered;
+ rFn = float64_to_floatx80(fpa11->fpreg[Fn].fDouble);
+ break;
+
+ case typeExtended:
+ //printk("extended.\n");
+ if (floatx80_is_nan(fpa11->fpreg[Fn].fExtended))
+ goto unordered;
+ rFn = fpa11->fpreg[Fn].fExtended;
+ break;
+
+ default: return 0;
+ }
+
+ if (CONSTANT_FM(opcode))
+ {
+ //printk("Fm is a constant: #%d.\n",Fm);
+ rFm = getExtendedConstant(Fm);
+ if (floatx80_is_nan(rFm))
+ goto unordered;
+ }
+ else
+ {
+ //printk("Fm = r%d which contains a ",Fm);
+ switch (fpa11->fType[Fm])
+ {
+ case typeSingle:
+ //printk("single.\n");
+ if (float32_is_nan(fpa11->fpreg[Fm].fSingle))
+ goto unordered;
+ rFm = float32_to_floatx80(fpa11->fpreg[Fm].fSingle);
+ break;
+
+ case typeDouble:
+ //printk("double.\n");
+ if (float64_is_nan(fpa11->fpreg[Fm].fDouble))
+ goto unordered;
+ rFm = float64_to_floatx80(fpa11->fpreg[Fm].fDouble);
+ break;
+
+ case typeExtended:
+ //printk("extended.\n");
+ if (floatx80_is_nan(fpa11->fpreg[Fm].fExtended))
+ goto unordered;
+ rFm = fpa11->fpreg[Fm].fExtended;
+ break;
+
+ default: return 0;
+ }
+ }
+
+ if (n_flag)
+ {
+ rFm.high ^= 0x8000;
+ }
+
+ return PerformComparisonOperation(rFn,rFm);
+
+ unordered:
+ /* ?? The FPA data sheet is pretty vague about this, in particular
+ about whether the non-E comparisons can ever raise exceptions.
+ This implementation is based on a combination of what it says in
+ the data sheet, observation of how the Acorn emulator actually
+ behaves (and how programs expect it to) and guesswork. */
+ flags |= CC_OVERFLOW;
+ flags &= ~(CC_ZERO | CC_NEGATIVE);
+
+ if (BIT_AC & readFPSR()) flags |= CC_CARRY;
+
+ if (e_flag) float_raise(float_flag_invalid);
+
+ writeConditionCodes(flags);
+ return 1;
+}