linux-user/sparc: Handle floating-point exceptions

Raise SIGFPE for ieee exceptions.

The other types, such as FSR_FTT_UNIMPFPOP, should not appear,
because we enable normal emulation of missing insns at the
start of sparc_cpu_realizefn().

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230216054516.1267305-15-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

linux-user/sparc/cpu_loop.c

@@ -297,6 +297,28 @@ void cpu_loop (CPUSPARCState *env)
             restore_window(env);
             break;
 
+        case TT_FP_EXCP:
+            {
+                int code = TARGET_FPE_FLTUNK;
+                target_ulong fsr = env->fsr;
+
+                if ((fsr & FSR_FTT_MASK) == FSR_FTT_IEEE_EXCP) {
+                    if (fsr & FSR_NVC) {
+                        code = TARGET_FPE_FLTINV;
+                    } else if (fsr & FSR_OFC) {
+                        code = TARGET_FPE_FLTOVF;
+                    } else if (fsr & FSR_UFC) {
+                        code = TARGET_FPE_FLTUND;
+                    } else if (fsr & FSR_DZC) {
+                        code = TARGET_FPE_FLTDIV;
+                    } else if (fsr & FSR_NXC) {
+                        code = TARGET_FPE_FLTRES;
+                    }
+                }
+                force_sig_fault(TARGET_SIGFPE, code, env->pc);
+            }
+            break;
+
         case EXCP_INTERRUPT:
             /* just indicate that signals should be handled asap */
             break;

target/sparc/cpu.h

@@ -197,8 +197,7 @@ enum {
 #define FSR_FTT2   (1ULL << 16)
 #define FSR_FTT1   (1ULL << 15)
 #define FSR_FTT0   (1ULL << 14)
-//gcc warns about constant overflow for ~FSR_FTT_MASK
-//#define FSR_FTT_MASK (FSR_FTT2 | FSR_FTT1 | FSR_FTT0)
+#define FSR_FTT_MASK (FSR_FTT2 | FSR_FTT1 | FSR_FTT0)
 #ifdef TARGET_SPARC64
 #define FSR_FTT_NMASK      0xfffffffffffe3fffULL
 #define FSR_FTT_CEXC_NMASK 0xfffffffffffe3fe0ULL