[patch] gas/config/tc-h8300.c (build_bytes): Assemble ldmac correctly.

[Kazu Hirata]

Hi,

Attached is a patch to fix a bug in h8300-hms-as. The original gas
does not assemble the first two lines of the following function
correctly. The last two lines are OK.

/* h8300-hms-gcc -ms -Wall -O2 -fomit-frame-pointer */
void
test ()
{
  __asm__ __volatile__ ("ldmac\ter4,mach");
  __asm__ __volatile__ ("ldmac\ter5,macl");
  __asm__ __volatile__ ("stmac\tmach,er4");
  __asm__ __volatile__ ("stmac\tmacl,er5");
}

Without the patch,

00000000 <_test>:
   0:	03 64       	03 64             ldmac	er4,mach <- incorrect
   2:	03 75       	03 75             ldmac	er5,mach <- incorrect
   4:	02 24       	02 24             stmac	mach,er4
   6:	02 35       	02 35             stmac	macl,er5
   8:	54 70       	54 70             rts	

With the patch, 

00000000 <_test>:
   0:	03 24       	03 24             ldmac	er4,mach <- correct
   2:	03 35       	03 35             ldmac	er5,macl <- correct
   4:	02 24       	02 24             stmac	mach,er4
   6:	02 35       	02 35             stmac	macl,er5
   8:	54 70       	54 70             rts	

The problem is that the variable 'd' in 'build_bytes ()' is always 0,
meaning the first operand, when processing MACREG. However, as you can
see from the assembly code, when we want to know which half of the mac
register (mach or macl) is used, we have to look at either the first
or second operand depending on ldmac or stmac.

By the way, the existing testsuite (gas/testsuite/gas/h8300/h8300.exp
and macs.s) is correct. The reason this bug got away with a failure is
a coincident that you would never expect. If you change the 32-bit
registers (er0 and er1) used in macs.s to some other 32-bit registers
(say, er4 and er5 just like the above example) and change h8300.exp
accordingly, the original gas would fail.

Thanks,

Kazu

===File ~/gnu/binutils/ChangeLog-tc-h8300===================
2000-06-24  Kazu Hirata  <kazu@hxi.com>

	* config/tc-h8300.c (build_bytes): Assemble ldmac correctly.

============================================================

===File ~/gnu/binutils/tc-h8300.patch=======================
Index: gas/config/tc-h8300.c
===================================================================
RCS file: /cvs/src/src/gas/config/tc-h8300.c,v
retrieving revision 1.6
diff -u -r1.6 tc-h8300.c
--- tc-h8300.c	2000/06/23 05:44:30	1.6
+++ tc-h8300.c	2000/06/24 23:03:03
@@ -1026,7 +1026,12 @@
 
 	  if (c & MACREG)
 	    {
-	      nib = 2 + operand[d].reg;
+	      if (operand[0].mode == MACREG)
+		/* stmac has mac[hl] as the first operand.  */
+		nib = 2 + operand[0].reg;
+	      else
+		/* ldmac has mac[hl] as the second operand.  */
+		nib = 2 + operand[1].reg;
 	    }
 	}
       nibble_count++;
============================================================