cpu: Add support for FPU exceptions

The floating point exeption handling was market TODO.  Implement it,
handling is very similar to SYSCALL so follow that pattern.  This was
tested with the new or1k-fpe test in or1k-tests and works as expected.

Signed-off-by: Stafford Horne <[email protected]>

Author: stffrdhrn

cpu-config.c

@@ -244,6 +244,7 @@ static void
 cpu_hardfloat (union param_val val, void *dat)
 {
   config.cpu.hardfloat = val.int_val;
+  cpu_state.sprs[SPR_CPUCFGR] |= SPR_CPUCFGR_OF32S;
 }
 /*---------------------------------------------------------------------------*/
 /*!Register the functions to handle a section cpu

cpu/or1k/except.c

@@ -99,6 +99,7 @@ except_handle (oraddr_t except, oraddr_t ea)
 	cpu_state.pc - (cpu_state.delay_insn ? 4 : 0);
       break;
       /* EPCR is loaded with address of next not-yet-executed instruction */
+    case EXCEPT_FPE:
     case EXCEPT_SYSCALL:
       cpu_state.sprs[SPR_EPCR_BASE] =
 	(cpu_state.pc + 4) - (cpu_state.delay_insn ? 4 : 0);

cpu/or32/execute.c

@@ -1113,12 +1113,10 @@ float_set_flags ()
 	 !!(float_exception_flags & float_flag_underflow),
 	 !!(float_exception_flags & float_flag_inexact));
   */
-  // TODO: Call FP exception is FPEE set and any of the flags were set
-  /*
-     if ((cpu_state.sprs[SPR_FPCSR] & SPR_FPCSR_FPEE) &
-     (|(cpu_state.sprs[SPR_FPCSR] & SPR_FPCSR_ALLF)))
-     except_handle (EXCEPT_FPE, cpu_state.iqueue.insn_addr);
-  */
+  // Call FP exception if FPEE set and any of the flags were set
+  if ((cpu_state.sprs[SPR_FPCSR] & SPR_FPCSR_FPEE) &&
+      (cpu_state.sprs[SPR_FPCSR] & SPR_FPCSR_ALLF))
+     except_handle (EXCEPT_FPE, cpu_state.sprs[SPR_EEAR_BASE]);
   // Now clear softfloat's flags:
   float_exception_flags = 0;