Changeset 00d2a828 in rtems

Timestamp:

05/28/97 20:36:35 (27 years ago)

Author:

Joel Sherrill <joel.sherrill@…>

Branches:

4.10, 4.11, 4.8, 4.9, 5, master

Children:

3a8256d

Parents:

5c995d7

Message:

Added support for context switching the data used by the gcc m68k
software floating point emulation code. Code implemented by
Karen Sara Looney <Karen.Looney@…> with much
email assistance from Joel.

Files:

• c/src/exec/rtems/headers/attr.h (modified) (1 diff)
• c/src/exec/rtems/include/rtems/rtems/attr.h (modified) (1 diff)
• c/src/exec/score/cpu/m68k/cpu.c (modified) (1 diff)
• c/src/exec/score/cpu/m68k/cpu.h (modified) (5 diffs)
• c/src/exec/score/cpu/m68k/cpu_asm.s (modified) (2 diffs)
• c/src/exec/score/src/thread.c (modified) (1 diff)
• cpukit/rtems/include/rtems/rtems/attr.h (modified) (1 diff)
• cpukit/score/cpu/m68k/cpu.c (modified) (1 diff)
• cpukit/score/src/thread.c (modified) (1 diff)

c/src/exec/rtems/headers/attr.h

@@ -48 +48 @@
 #define RTEMS_PRIORITY_CEILING    0x00000040
 
-#if ( CPU_HARDWARE_FP == TRUE )
+#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
 #define ATTRIBUTES_NOT_SUPPORTED       0
 #else

c/src/exec/rtems/include/rtems/rtems/attr.h

@@ -48 +48 @@
 #define RTEMS_PRIORITY_CEILING    0x00000040
 
-#if ( CPU_HARDWARE_FP == TRUE )
+#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
 #define ATTRIBUTES_NOT_SUPPORTED       0
 #else

c/src/exec/score/cpu/m68k/cpu.c

@@ -178 +178 @@
 };
 #endif
+
+/*PAGE
+ *
+ *  The following code context switches the software FPU emulation
+ *  code provided with GCC.
+ */
+
+#if (CPU_SOFTWARE_FP == TRUE)
+extern Context_Control_fp _fpCCR;
+
+void CPU_Context_save_fp (void **fp_context_ptr)
+{
+  Context_Control_fp *fp;
+
+  fp = (Context_Control_fp *) *fp_context_ptr;
+
+  *fp = _fpCCR;
+}
+
+void CPU_Context_restore_fp (void **fp_context_ptr)
+{
+  Context_Control_fp *fp;
+
+  fp = (Context_Control_fp *) *fp_context_ptr;
+
+  _fpCCR = *fp;
+}
+#endif
+

c/src/exec/score/cpu/m68k/cpu.h

@@ -53 +53 @@
  *  Some family members have no FP, some have an FPU such as the
  *  MC68881/MC68882 for the MC68020, others have it built in (MC68030, 040).
+ *
+ *  NOTE:  If on a CPU without hardware FP, then one can use software
+ *         emulation.  The gcc software FP emulation code has data which
+ *         must be contexted switched on a per task basis.
  */
 
 #if ( M68K_HAS_FPU == 1 )
 #define CPU_HARDWARE_FP     TRUE
+#define CPU_SOFTWARE_FP     FALSE
 #else
 #define CPU_HARDWARE_FP     FALSE
+#if defined(__GCC__)
+#define CPU_SOFTWARE_FP     TRUE
+#else
+#define CPU_SOFTWARE_FP     FALSE
+#endif
 #endif
 
@@ -109 +119 @@
 
 /*
+ *  Floating point context ares
+ */
+
+#if (CPU_SOFTWARE_FP == TRUE)
+
+/*
+ *  This is the same as gcc's view of the software FP condition code
+ *  register _fpCCR.  The implementation of the emulation code is
+ *  in the gcc-VERSION/config/m68k directory.  This structure is
+ *  correct as of gcc 2.7.2.2.
+ */
+
+typedef struct {
+  unsigned16   _exception_bits;
+  unsigned16   _trap_enable_bits;
+  unsigned16   _sticky_bits;
+  unsigned16   _rounding_mode;
+  unsigned16   _format;
+  unsigned16   _last_operation;
+  union {
+    float sf;
+    double df;
+  } _operand1;
+  union {
+    float sf;
+    double df;
+  } _operand2;
+} Context_Control_fp;
+
+#else 
+
+/*
  *  FP context save area for the M68881/M68882 numeric coprocessors.
  */
@@ -118 +160 @@
                                     /*     4 bytes for non-null flag     */
 } Context_Control_fp;
+#endif
 
 /*
@@ -292 +335 @@
   }
 
+/*
+ *  Floating Point Context Area Support routines
+ */
+
+#if (CPU_SOFTWARE_FP == TRUE)
+
+/*
+ *  This software FP implementation is only for GCC.
+ */
+
+#define _CPU_Context_Fp_start( _base, _offset ) \
+   ((void *) _Addresses_Add_offset( (_base), (_offset) ) )
+
+
+#define _CPU_Context_Initialize_fp( _fp_area ) \
+   { \
+   Context_Control_fp *_fp; \
+   _fp = *(Context_Control_fp **)_fp_area; \
+   _fp->_exception_bits = 0; \
+   _fp->_trap_enable_bits = 0; \
+   _fp->_sticky_bits = 0; \
+   _fp->_rounding_mode = 0;  /* ROUND_TO_NEAREST */ \
+   _fp->_format = 0;         /* NIL */ \
+   _fp->_last_operation = 0;  /* NOOP */ \
+   _fp->_operand1.df = 0; \
+   _fp->_operand2.df = 0; \
+   }
+#else
 #define _CPU_Context_Fp_start( _base, _offset ) \
    ((void *) \
@@ -306 +377 @@
      *(_fp_area) = (unsigned8 *)(_fp_context); \
    }
+#endif
 
 /* end of Context handler macros */

c/src/exec/score/cpu/m68k/cpu_asm.s

@@ -52 +52 @@
  *         CPU_FP_CONTEXT_SIZE is higher than expected to account for the
  *         -1 pushed at end of this sequence.
- */
+ *
+ *         Neither of these entries is required if we have software FPU
+ *         emulation.  But if we don't have an FPU or emulation, then
+ *         we need the stub versions of these routines.
+ */
+
+#if (CPU_SOFTWARE_FP == FALSE)
 
 .set FPCONTEXT_ARG,   4                    | save FP context argument
@@ -87 +93 @@
 #endif
         rts
+#endif
 
 /*PAGE

c/src/exec/score/src/thread.c

@@ -213 +213 @@
  
 
-#if ( CPU_HARDWARE_FP == TRUE )
+#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
    /*
     *  don't need to worry about saving BSP's floating point state

cpukit/rtems/include/rtems/rtems/attr.h

@@ -48 +48 @@
 #define RTEMS_PRIORITY_CEILING    0x00000040
 
-#if ( CPU_HARDWARE_FP == TRUE )
+#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
 #define ATTRIBUTES_NOT_SUPPORTED       0
 #else

cpukit/score/cpu/m68k/cpu.c

@@ -178 +178 @@
 };
 #endif
+
+/*PAGE
+ *
+ *  The following code context switches the software FPU emulation
+ *  code provided with GCC.
+ */
+
+#if (CPU_SOFTWARE_FP == TRUE)
+extern Context_Control_fp _fpCCR;
+
+void CPU_Context_save_fp (void **fp_context_ptr)
+{
+  Context_Control_fp *fp;
+
+  fp = (Context_Control_fp *) *fp_context_ptr;
+
+  *fp = _fpCCR;
+}
+
+void CPU_Context_restore_fp (void **fp_context_ptr)
+{
+  Context_Control_fp *fp;
+
+  fp = (Context_Control_fp *) *fp_context_ptr;
+
+  _fpCCR = *fp;
+}
+#endif
+

cpukit/score/src/thread.c

@@ -213 +213 @@
  
 
-#if ( CPU_HARDWARE_FP == TRUE )
+#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
    /*
     *  don't need to worry about saving BSP's floating point state