[rfa:i386] Add mmx registers

[Andrew Cagney <ac131313 at ges dot redhat dot com>]

Hello,

This adds mmx registers to the i386.

Several notes:

It depends on an earlier patch I submitted that eliminates 
register_byte() and register_raw_size() from the i386.

It probably works better if the ``info vector'' command is added.

If someone has a bit of code for testing this, I'm most interested.  I 
think its correct :-)

Assuming I've got it right ..., yes, it is that easy :-)

comments? ok?
Andrew
2002-08-10  Andrew Cagney  <cagney@redhat.com>

	* i386-tdep.h (i386_register_byte, i386_register_raw_size): Delete
	declarations.
	* i386-tdep.c (i386_register_name): Handle mmx registers.
	(is_mmx_regnum): New function.
	(i386_mmx_names): New array.
	(nr_mmx_regs): New variable.
	(i386_pseudo_register_read): New function.
	(i386_pseudo_register_write): New function.
	(mmx_regnum_to_fp_regnum): New function. Code from Fernando Nasser.

diff --exclude *CVS* --exclude *#* --exclude *~* --exclude *%* --exclude *.orig --exclude *.rej --exclude *diffs --exclude new-* --exclude old-* --exclude *-new --exclude *-old -u /home/cagney/2002-08-09-p4-cleanup/src/gdb/i386-tdep.c ./i386-tdep.c
--- /home/cagney/2002-08-09-p4-cleanup/src/gdb/i386-tdep.c	Fri Aug  9 20:44:31 2002
+++ ./i386-tdep.c	Sat Aug 10 02:02:14 2002
@@ -56,6 +56,23 @@
   "mxcsr"
 };
 
+/* MMX registers.  */
+
+static char *i386_mmx_names[] =
+{
+  "mm0", "mm1", "mm2", "mm3",
+  "mm4", "mm5", "mm6", "mm7"
+};
+static const int nr_mmx_regs = (sizeof (i386_mmx_names)
+				/ sizeof (i386_mmx_names[0]));
+#define MM0_REGNUM (NUM_REGS)
+
+static int
+is_mmx_regnum (int reg)
+{
+  return (reg >= MM0_REGNUM && reg < MM0_REGNUM + nr_mmx_regs);
+}
+
 /* Return the name of register REG.  */
 
 const char *
@@ -63,9 +80,10 @@
 {
   if (reg < 0)
     return NULL;
+  if (is_mmx_regnum (reg))
+    return i386_mmx_names[reg - MM0_REGNUM];
   if (reg >= sizeof (i386_register_names) / sizeof (*i386_register_names))
     return NULL;
-
   return i386_register_names[reg];
 }
 
@@ -1079,9 +1097,60 @@
   if (IS_SSE_REGNUM (regnum))
     return builtin_type_vec128i;
 
+  if (is_mmx_regnum (regnum))
+    return builtin_type_vec64i;
+
   return builtin_type_int;
 }
 
+/* Map a cooked register onto a raw register or memory.  For the i386,
+   the MMX registers need to be mapped onto floating point registers.  */
+
+static int
+mmx_regnum_to_fp_regnum (struct regcache *regcache, int regnum)
+{
+  int mmxi = regnum - MM0_REGNUM;
+  int fstat = regcache_raw_read_as_address (regcache, FSTAT_REGNUM);
+  int tos = (fstat >> 11) & 0x7;
+  int fpi = (mmxi + tos) % 8;
+  return FP0_REGNUM + fpi;
+}
+
+static void
+i386_pseudo_register_read (struct gdbarch *gdbarch, struct regcache *regcache,
+			   int regnum, void *buf)
+{
+  if (is_mmx_regnum (regnum))
+    {
+      char *mmx_buf = alloca (MAX_REGISTER_RAW_SIZE);
+      int fpnum = mmx_regnum_to_fp_regnum (regcache, regnum);
+      regcache_raw_read (regcache, fpnum, mmx_buf);
+      /* Extract (always little endian).  */
+      memcpy (buf, mmx_buf, REGISTER_RAW_SIZE (regnum));
+    }
+  else
+    regcache_raw_read (regcache, regnum, buf);
+}
+
+static void
+i386_pseudo_register_write (struct gdbarch *gdbarch, struct regcache *regcache,
+			    int regnum, const void *buf)
+{
+  if (is_mmx_regnum (regnum))
+    {
+      char *mmx_buf = alloca (MAX_REGISTER_RAW_SIZE);
+      int fpnum = mmx_regnum_to_fp_regnum (regcache, regnum);
+      /* Read ...  */
+      regcache_raw_read (regcache, fpnum, mmx_buf);
+      /* ... Modify ... (always little endian).  */
+      memcpy (mmx_buf, buf, REGISTER_RAW_SIZE (regnum));
+      /* ... Write.  */
+      regcache_raw_write (regcache, fpnum, mmx_buf);
+    }
+  else
+    regcache_raw_write (regcache, regnum, buf);
+}
+
 /* Return true iff register REGNUM's virtual format is different from
    its raw format.  Note that this definition assumes that the host
    supports IEEE 32-bit floats, since it doesn't say that SSE
@@ -1474,6 +1543,11 @@
   set_gdbarch_saved_pc_after_call (gdbarch, i386_saved_pc_after_call);
   set_gdbarch_frame_num_args (gdbarch, i386_frame_num_args);
   set_gdbarch_pc_in_sigtramp (gdbarch, i386_pc_in_sigtramp);
+
+  /* Wire in the MMX registers.  */
+  set_gdbarch_num_pseudo_regs (gdbarch, nr_mmx_regs);
+  set_gdbarch_pseudo_register_read (gdbarch, i386_pseudo_register_read);
+  set_gdbarch_pseudo_register_write (gdbarch, i386_pseudo_register_write);
 
   /* Hook in ABI-specific overrides, if they have been registered.  */
   gdbarch_init_osabi (info, gdbarch, osabi);