or1k: Support for softfloat to emulate hw exceptions

This allows the openrisc softfloat implementation to set exceptions.
This also sets the correct tininess after rounding value to be
consistent with hardware and simulator implementations.

libgcc/ChangeLog:

	* config/or1k/sfp-machine.h (FP_RND_NEAREST, FP_RND_ZERO,
	FP_RND_PINF, FP_RND_MINF, FP_RND_MASK, FP_EX_OVERFLOW,
	FP_EX_UNDERFLOW, FP_EX_INEXACT, FP_EX_INVALID, FP_EX_DIVZERO,
	FP_EX_ALL): New constant macros.
	(_FP_DECL_EX, FP_ROUNDMODE, FP_INIT_ROUNDMODE,
	FP_HANDLE_EXCEPTIONS): New macros.
	(_FP_TININESS_AFTER_ROUNDING): Change to 1.

diff --git a/libgcc/config/or1k/sfp-machine.h b/libgcc/config/or1k/sfp-machine.h
index 5da9e84990d6dc495ad1858ad0a3bfd2124903c5..eebe5b0578edaceaedc48ecce5cdda76fe788855 100644 (file)
--- a/libgcc/config/or1k/sfp-machine.h
+++ b/libgcc/config/or1k/sfp-machine.h
@@ -41,12 +41,51 @@
     R##_c = FP_CLS_NAN;                                                \
   } while (0)
 
+/* Handle getting and setting rounding mode for soft fp operations.  */
+
+#define FP_RND_NEAREST         (0x0 << 1)
+#define FP_RND_ZERO            (0x1 << 1)
+#define FP_RND_PINF            (0x2 << 1)
+#define FP_RND_MINF            (0x3 << 1)
+#define FP_RND_MASK            (0x3 << 1)
+
+#define FP_EX_OVERFLOW         1 << 3
+#define FP_EX_UNDERFLOW                1 << 4
+#define FP_EX_INEXACT          1 << 8
+#define FP_EX_INVALID          1 << 9
+#define FP_EX_DIVZERO          1 << 11
+#define FP_EX_ALL \
+       (FP_EX_INVALID | FP_EX_DIVZERO | FP_EX_OVERFLOW | FP_EX_UNDERFLOW \
+        | FP_EX_INEXACT)
+
+#define _FP_DECL_EX \
+  unsigned int _fpcsr __attribute__ ((unused)) = FP_RND_NEAREST
+
+#define FP_ROUNDMODE (_fpcsr & FP_RND_MASK)
+
+#ifdef __or1k_hard_float__
+#define FP_INIT_ROUNDMODE                                      \
+do {                                                           \
+  __asm__ volatile ("l.mfspr %0,r0,20" : "=r" (_fpcsr));       \
+} while (0)
+
+#define FP_HANDLE_EXCEPTIONS                                   \
+do {                                                           \
+  if (__builtin_expect (_fex, 0))                              \
+    {                                                          \
+      _fpcsr &= ~FP_EX_ALL;                                    \
+      _fpcsr |= _fex;                                          \
+      __asm__ volatile ("l.mtspr r0,%0,20" : : "r" (_fpcsr));  \
+    }                                                          \
+} while (0)
+#endif
+
 #define        __LITTLE_ENDIAN 1234
 #define        __BIG_ENDIAN    4321
 
 #define __BYTE_ORDER __BIG_ENDIAN
 
-#define _FP_TININESS_AFTER_ROUNDING 0
+#define _FP_TININESS_AFTER_ROUNDING 1
 
 /* Define ALIASNAME as a strong alias for NAME.  */
 # define strong_alias(name, aliasname) _strong_alias(name, aliasname)