diff --git a/gdbstub.c b/gdbstub.c
index 139bc25fca..37dc764f52 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -563,7 +563,7 @@ static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
         ptr += sizeof(target_ulong);
       }
 
-    *(target_ulong *)ptr = tswapl(env->CP0_Status);
+    *(target_ulong *)ptr = (int32_t)tswap32(env->CP0_Status);
     ptr += sizeof(target_ulong);
 
     *(target_ulong *)ptr = tswapl(env->LO[0][env->current_tc]);
@@ -575,7 +575,7 @@ static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
     *(target_ulong *)ptr = tswapl(env->CP0_BadVAddr);
     ptr += sizeof(target_ulong);
 
-    *(target_ulong *)ptr = tswapl(env->CP0_Cause);
+    *(target_ulong *)ptr = (int32_t)tswap32(env->CP0_Cause);
     ptr += sizeof(target_ulong);
 
     *(target_ulong *)ptr = tswapl(env->PC[env->current_tc]);
@@ -585,19 +585,34 @@ static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
       {
         for (i = 0; i < 32; i++)
           {
-            *(target_ulong *)ptr = tswapl(env->fpu->fpr[i].fs[FP_ENDIAN_IDX]);
+            if (env->CP0_Status & (1 << CP0St_FR))
+              *(target_ulong *)ptr = tswapl(env->fpu->fpr[i].d);
+            else
+              *(target_ulong *)ptr = tswap32(env->fpu->fpr[i].w[FP_ENDIAN_IDX]);
             ptr += sizeof(target_ulong);
           }
 
-        *(target_ulong *)ptr = tswapl(env->fpu->fcr31);
+        *(target_ulong *)ptr = (int32_t)tswap32(env->fpu->fcr31);
         ptr += sizeof(target_ulong);
 
-        *(target_ulong *)ptr = tswapl(env->fpu->fcr0);
+        *(target_ulong *)ptr = (int32_t)tswap32(env->fpu->fcr0);
         ptr += sizeof(target_ulong);
       }
 
-    /* 32 FP registers, fsr, fir, fp.  Not yet implemented.  */
-    /* what's 'fp' mean here?  */
+    /* "fp", pseudo frame pointer. Not yet implemented in gdb. */
+    *(target_ulong *)ptr = 0;
+    ptr += sizeof(target_ulong);
+
+    /* Registers for embedded use, we just pad them. */
+    for (i = 0; i < 16; i++)
+      {
+        *(target_ulong *)ptr = 0;
+        ptr += sizeof(target_ulong);
+      }
+
+    /* Processor ID. */
+    *(target_ulong *)ptr = (int32_t)tswap32(env->CP0_PRid);
+    ptr += sizeof(target_ulong);
 
     return ptr - mem_buf;
 }
@@ -647,15 +662,17 @@ static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
       {
         for (i = 0; i < 32; i++)
           {
-            env->fpu->fpr[i].fs[FP_ENDIAN_IDX] = tswapl(*(target_ulong *)ptr);
+            if (env->CP0_Status & (1 << CP0St_FR))
+              env->fpu->fpr[i].d = tswapl(*(target_ulong *)ptr);
+            else
+              env->fpu->fpr[i].w[FP_ENDIAN_IDX] = tswapl(*(target_ulong *)ptr);
             ptr += sizeof(target_ulong);
           }
 
-        env->fpu->fcr31 = tswapl(*(target_ulong *)ptr) & 0x0183FFFF;
+        env->fpu->fcr31 = tswapl(*(target_ulong *)ptr) & 0xFF83FFFF;
         ptr += sizeof(target_ulong);
 
-        env->fpu->fcr0 = tswapl(*(target_ulong *)ptr);
-        ptr += sizeof(target_ulong);
+        /* The remaining registers are assumed to be read-only. */
 
         /* set rounding mode */
         RESTORE_ROUNDING_MODE;