RE: [PATCH] Fix for ldm/stm instructions in H8S

["Asgari J. Jinia" <AsgariJ at KPITCummins dot com>]

Hi Kazu,

Thanks for your suggestion. The test for register validity suggested by you is simpler so we can go ahead with that. Please find attached a test program which was used for testing and results were found ok. Please find below patch.

Regards,
Asgari Jinia

------------------ Start Of Patch ---------------------------
2003-11-07  Asgari Jinia  <asgarij@kpitcummins.com>

	* config/tc-h8300.c (md_assemble): Check operands validity for
	ldm/stm.
	(get_operand): Check register pair's validity as per technical
	note TN-H8*-193A/E from Renesas.


--- tc-h8300.old.c	Fri Nov  7 17:59:46 2003
+++ tc-h8300.c	Fri Nov  7 18:17:20 2003
@@ -622,14 +622,14 @@ get_operand (ptr, op, direction)
       low = src[2] - '0';
       high = src[6] - '0';
 
-      if (high == low)
-	as_bad (_("Invalid register list for ldm/stm\n"));
-
-      if (high < low)
+       /* Check register pair's validity as per tech note TN-H8*-193A/E
+         from Renesas.  */
+      if (!(low == 0 && (high == 1 || high == 2 || high == 3))
+          && !(low == 2 && high == 3)
+          && !(low == 4 && (high == 5 || high == 6)))
+        {
 	as_bad (_("Invalid register list for ldm/stm\n"));
-
-      if (high - low > 3)
-	as_bad (_("Invalid register list for ldm/stm)\n"));
+        }
 
       /* Even sicker.  We encode two registers into op->reg.  One
 	 for the low register to save, the other for the high
@@ -1965,6 +1965,32 @@ md_assemble (str)
   *op_end = c;
   prev_instruction = instruction;
 
+  /* Now we have operands from instuction.  Let's check them out for
+     ldm and stm.  */
+  if (OP_KIND (instruction->opcode->how) == O_LDM)
+    {
+      /* The first operand must be @er7+, and the second operand must
+          be a register pair.  */
+      if ((operand[0].mode != RSINC)
+           || (operand[0].reg != 7)
+           || ((operand[1].reg & 0x80000000) == 0))
+        {
+          as_bad (_("invalid operand in ldm"));
+        }
+    }
+
+  if (OP_KIND (instruction->opcode->how) == O_STM)
+    {
+      /* The first operand must be a register pair, and the second
+          operand must be @-er7.  */
+      if (((operand[0].reg & 0x80000000) == 0)
+            || (operand[1].mode != RDDEC)
+            || (operand[1].reg != 7))
+        {
+          as_bad (_("invalid operand in stm"));
+        }
+    }
+
   size = SN;
   if (dot)
     {
------------------ End Of Patch ---------------------------

-----Original Message-----
From: Kazu Hirata [mailto:kazu@cs.umass.edu]
Sent: Thursday, November 06, 2003 4:24 AM
To: Asgari J. Jinia
Cc: binutils@sources.redhat.com
Subject: Re: [PATCH] Fix for ldm/stm instructions in H8S


Hi Asgari,

> 2003-11-05 Asgari Jinia <asgarij@kpitcummins.com>
> 	* config/tc-h8300.c (md_assemble) : Check operands validity for ldm/stm.
> 	(get_operand) : Check register pair's validity as per tech note TN-H8*-193A/E from Renesas.

What about a simpler test that checks all possibilities of low and
high (see attached)?  Someone reading the code does not have to
decipher it.

By the way, I fixed minor things like formatting.  Next time you
contribute something, please follow the GNU Coding Standards,
available at:

  http://www.gnu.org/prep/standards_toc.html

I assume you actually fed some invalid code to get these error
messages.  The patch looks good.  I leave the approval up to other
people.

Otherwise

Kazu Hirata

2003-11-05  Asgari Jinia  <asgarij@kpitcummins.com>

	* config/tc-h8300.c (md_assemble): Check operands validity for
	ldm/stm.
	(get_operand): Check register pair's validity as per technical
	note TN-H8*-193A/E from Renesas.

Index: tc-h8300.c
===================================================================
RCS file: /cvs/src/src/gas/config/tc-h8300.c,v
retrieving revision 1.37
diff -c -r1.37 tc-h8300.c
*** tc-h8300.c	17 Oct 2003 10:23:33 -0000	1.37
--- tc-h8300.c	5 Nov 2003 22:36:46 -0000
***************
*** 622,635 ****
        low = src[2] - '0';
        high = src[6] - '0';
  
!       if (high == low)
! 	as_bad (_("Invalid register list for ldm/stm\n"));
! 
!       if (high < low)
! 	as_bad (_("Invalid register list for ldm/stm\n"));
! 
!       if (high - low > 3)
! 	as_bad (_("Invalid register list for ldm/stm)\n"));
  
        /* Even sicker.  We encode two registers into op->reg.  One
  	 for the low register to save, the other for the high
--- 622,635 ----
        low = src[2] - '0';
        high = src[6] - '0';
  
!       /* Check register pair's validity as per tech note TN-H8*-193A/E
! 	 from Renesas.  */
!       if (!(low == 0 && (high == 1 || high == 2 || high == 3))
! 	  && !(low == 2 && high == 3)
! 	  && !(low == 4 && (high == 5 || high == 6)))
! 	{
! 	  as_bad (_("Invalid register list for ldm/stm\n"));
! 	}
  
        /* Even sicker.  We encode two registers into op->reg.  One
  	 for the low register to save, the other for the high
***************
*** 1965,1970 ****
--- 1965,1995 ----
    *op_end = c;
    prev_instruction = instruction;
  
+    /* Now we have operands from instuction.  Let's check them out for
+       ldm and stm.  */
+    if (OP_KIND (instruction->opcode->how) == O_LDM)
+      {
+        /* The first operand must be @er7+, and the second operand must
+ 	  be a register pair.  */
+        if ((operand[0].mode != RSINC)
+ 	   || (operand[0].reg != 7)
+ 	   || ((operand[1].reg & 0x80000000) == 0))
+          {
+            as_bad (_("invalid operand in ldm"));
+          }
+      }
+  
+    if (OP_KIND (instruction->opcode->how) == O_STM)
+      {
+        /* The first operand must be a register pair, and the second
+ 	  operand must be @-er7.  */
+        if (((operand[0].reg & 0x80000000) == 0)
+ 	   || (operand[1].mode != RDDEC) || (operand[1].reg != 7))
+          {
+            as_bad (_("invalid operand in stm"));
+          }
+      }
+  
    size = SN;
    if (dot)
      {

Attachment: main.s
Description: main.s