target-mips: fix 64-bit FPU config for user-mode emulation

FR bit should be initialized to 1 for MIPS64, under condition that this
bit is writable and that CPU has an FPU unit. It should be initialized to
zero for MIPS32.
This fixes different MIPS32 issues with FPU instructions whose behaviour
defaulted to 64-bit FPU mode.
Signed-off-by: NPetar Jovanovic <petar.jovanovic@imgtec.com>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

target-mips/translate.c

@@ -15983,10 +15983,13 @@ void cpu_state_reset(CPUMIPSState *env)
     if (env->CP0_Config3 & (1 << CP0C3_DSPP)) {
         env->CP0_Status |= (1 << CP0St_MX);
     }
-    /* Enable 64-bit FPU if the target cpu supports it.  */
-    if (env->active_fpu.fcr0 & (1 << FCR0_F64)) {
+# if defined(TARGET_MIPS64)
+    /* For MIPS64, init FR bit to 1 if FPU unit is there and bit is writable. */
+    if ((env->CP0_Config1 & (1 << CP0C1_FP)) &&
+        (env->CP0_Status_rw_bitmask & (1 << CP0St_FR))) {
         env->CP0_Status |= (1 << CP0St_FR);
     }
+# endif
 #else
     if (env->hflags & MIPS_HFLAG_BMASK) {
         /* If the exception was raised from a delay slot,