Re: [rfa:i386] Add mmx registers

[Andrew Cagney <ac131313@ges.redhat.com>]

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> Andrew Cagney <ac131313@ges.redhat.com> writes:
> 
> 
> Hello,
> 
> This adds mmx registers to the i386.
> 
> 
> Great, a few nits though :-(
> 
> * Please rename is_mmx_regnum() to mmx_regnum_p().
> 
> * Please rename nr_mmx_regs to mmx_num_regs.
> 
> * Why do you use regcache_raw_read_as_address() in
>   mmx_regnum_to_fp_regnum?  Looks misleading to me...
> 
> (because I happen to know what the function does :-)
> I'll rename the function to ..._as_longest().
> 
> I'll fix the others.

Done, this is what I committed.

It also includes raw versions of the ..._unsigned() functions since the 
mmx code needs to access the raw register cache.

Andrew


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2002-08-13  Andrew Cagney  <cagney@redhat.com>

	* i386-tdep.c (i386_register_name): Handle mmx registers.
	(mmx_regnum_p): New function.
	(i386_mmx_names): New array.
	(mmx_num_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.

	* regcache.c (regcache_raw_read_unsigned): New function.
	(regcache_raw_read_signed): New function.
	* regcache.h (regcache_raw_read_unsigned): Declare.
	(regcache_raw_read_signed): Declare.

Index: i386-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/i386-tdep.c,v
retrieving revision 1.75
diff -u -r1.75 i386-tdep.c
--- i386-tdep.c	13 Aug 2002 13:58:50 -0000	1.75
+++ i386-tdep.c	13 Aug 2002 14:31:01 -0000
@@ -56,6 +56,23 @@
   "mxcsr"
 };
 
+/* MMX registers.  */
+
+static char *i386_mmx_names[] =
+{
+  "mm0", "mm1", "mm2", "mm3",
+  "mm4", "mm5", "mm6", "mm7"
+};
+static const int mmx_num_regs = (sizeof (i386_mmx_names)
+				 / sizeof (i386_mmx_names[0]));
+#define MM0_REGNUM (NUM_REGS)
+
+static int
+mmx_regnum_p (int reg)
+{
+  return (reg >= MM0_REGNUM && reg < MM0_REGNUM + mmx_num_regs);
+}
+
 /* Return the name of register REG.  */
 
 const char *
@@ -63,6 +80,8 @@
 {
   if (reg < 0)
     return NULL;
+  if (mmx_regnum_p (reg))
+    return i386_mmx_names[reg - MM0_REGNUM];
   if (reg >= sizeof (i386_register_names) / sizeof (*i386_register_names))
     return NULL;
 
@@ -1090,9 +1109,64 @@
   if (IS_SSE_REGNUM (regnum))
     return builtin_type_vec128i;
 
+  if (mmx_regnum_p (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;
+  ULONGEST fstat;
+  int tos;
+  int fpi;
+  mmxi = regnum - MM0_REGNUM;
+  regcache_raw_read_unsigned (regcache, FSTAT_REGNUM, &fstat);
+  tos = (fstat >> 11) & 0x7;
+  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 (mmx_regnum_p (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 (mmx_regnum_p (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
@@ -1485,6 +1559,11 @@
   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, mmx_num_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);
Index: regcache.c
===================================================================
RCS file: /cvs/src/src/gdb/regcache.c,v
retrieving revision 1.51
diff -u -r1.51 regcache.c
--- regcache.c	13 Aug 2002 13:58:50 -0000	1.51
+++ regcache.c	13 Aug 2002 14:31:02 -0000
@@ -661,6 +661,31 @@
 }
 
 void
+regcache_raw_read_signed (struct regcache *regcache, int regnum, LONGEST *val)
+{
+  char *buf;
+  gdb_assert (regcache != NULL);
+  gdb_assert (regnum >= 0 && regnum < regcache->descr->nr_raw_registers);
+  buf = alloca (regcache->descr->sizeof_register[regnum]);
+  regcache_raw_read (regcache, regnum, buf);
+  (*val) = extract_signed_integer (buf,
+				   regcache->descr->sizeof_register[regnum]);
+}
+
+void
+regcache_raw_read_unsigned (struct regcache *regcache, int regnum,
+			    ULONGEST *val)
+{
+  char *buf;
+  gdb_assert (regcache != NULL);
+  gdb_assert (regnum >= 0 && regnum < regcache->descr->nr_raw_registers);
+  buf = alloca (regcache->descr->sizeof_register[regnum]);
+  regcache_raw_read (regcache, regnum, buf);
+  (*val) = extract_unsigned_integer (buf,
+				     regcache->descr->sizeof_register[regnum]);
+}
+
+void
 read_register_gen (int regnum, char *buf)
 {
   gdb_assert (current_regcache != NULL);
Index: regcache.h
===================================================================
RCS file: /cvs/src/src/gdb/regcache.h,v
retrieving revision 1.13
diff -u -r1.13 regcache.h
--- regcache.h	13 Aug 2002 13:58:50 -0000	1.13
+++ regcache.h	13 Aug 2002 14:31:02 -0000
@@ -38,6 +38,10 @@
 void regcache_raw_read (struct regcache *regcache, int rawnum, void *buf);
 void regcache_raw_write (struct regcache *regcache, int rawnum,
 			 const void *buf);
+extern void regcache_raw_read_signed (struct regcache *regcache,
+				      int regnum, LONGEST *val);
+extern void regcache_raw_read_unsigned (struct regcache *regcache,
+					int regnum, ULONGEST *val);
 int regcache_valid_p (struct regcache *regcache, int regnum);
 
 /* Transfer a cooked register [0..NUM_REGS+NUM_PSEUDO_REGS).  */