[PATCH/RFA] h8300 sim: add daa and das insns

[PATCH/RFA] h8300 sim: add daa and das insns

[Michael Snyder]

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Here's my implementation of daa/das:

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2003-04-07  Michael Snyder  <msnyder@redhat.com>

	* compile.c (sim_resume): Implement daa and das insns.

Index: compile.c
===================================================================
RCS file: /cvs/cvsfiles/devo/sim/h8300/compile.c,v
retrieving revision 1.70
diff -p -r1.70 compile.c
*** compile.c	2003/03/27 22:01:29	1.70
--- compile.c	2003/04/08 06:20:31
*************** sim_resume (SIM_DESC sd, int step, int s
*** 2138,2143 ****
--- 2146,2202 ----
  	  }
  	  goto next;
  
+ 	case O (O_DAA, SB):
+ 	  /* Decimal Adjust Addition.  This is for BCD arithmetic.  */
+ 	  res = GET_B_REG (code->src.reg);
+ 	  if (!c && (0 <= (res >>  4) && (res >>  4) <= 9) && 
+ 	      !h && (0 <= (res & 0xf) && (res & 0xf) <= 9))
+ 	    res = res;		/* Value added == 0.  */
+ 	  else if (!c && (0  <= (res >>  4) && (res >>  4) <=  8) && 
+ 		   !h && (10 <= (res & 0xf) && (res & 0xf) <= 15))
+ 	    res = res + 0x6;		/* Value added == 6.  */
+ 	  else if (!c && (0 <= (res >>  4) && (res >>  4) <= 9) && 
+ 		    h && (0 <= (res & 0xf) && (res & 0xf) <= 3))
+ 	    res = res + 0x6;		/* Value added == 6.  */
+ 	  else if (!c && (10 <= (res >>  4) && (res >>  4) <= 15) && 
+ 		   !h && (0  <= (res & 0xf) && (res & 0xf) <=  9))
+ 	    res = res + 0x60;		/* Value added == 60.  */
+ 	  else if (!c && (9  <= (res >>  4) && (res >>  4) <= 15) && 
+ 		   !h && (10 <= (res & 0xf) && (res & 0xf) <= 15))
+ 	    res = res + 0x66;		/* Value added == 66.  */
+ 	  else if (!c && (10 <= (res >>  4) && (res >>  4) <= 15) && 
+ 		    h && (0  <= (res & 0xf) && (res & 0xf) <=  3))
+ 	    res = res + 0x66;		/* Value added == 66.  */
+ 	  else if ( c && (1 <= (res >>  4) && (res >>  4) <= 2) && 
+ 		   !h && (0 <= (res & 0xf) && (res & 0xf) <= 9))
+ 	    res = res + 0x60;		/* Value added == 60.  */
+ 	  else if ( c && (1  <= (res >>  4) && (res >>  4) <=  2) && 
+ 		   !h && (10 <= (res & 0xf) && (res & 0xf) <= 15))
+ 	    res = res + 0x66;		/* Value added == 66.  */
+ 	  else if (c && (1 <= (res >>  4) && (res >>  4) <= 3) && 
+ 		   h && (0 <= (res & 0xf) && (res & 0xf) <= 3))
+ 	    res = res + 0x66;		/* Value added == 66.  */
+ 
+ 	  goto alu8;
+ 
+ 	case O (O_DAS, SB):
+ 	  /* Decimal Adjust Subtraction.  This is for BCD arithmetic.  */
+ 	  res = GET_B_REG (code->src.reg); /* FIXME fetch, fetch2... */
+ 	  if (!c && (0 <= (res >>  4) && (res >>  4) <= 9) && 
+ 	      !h && (0 <= (res & 0xf) && (res & 0xf) <= 9))
+ 	    res = res;		/* Value added == 0.  */
+ 	  else if (!c && (0 <= (res >>  4) && (res >>  4) <=  8) && 
+ 		    h && (6 <= (res & 0xf) && (res & 0xf) <= 15))
+ 	    res = res + 0xfa;		/* Value added == 0xfa.  */
+ 	  else if ( c && (7 <= (res >>  4) && (res >>  4) <= 15) && 
+ 		   !h && (0 <= (res & 0xf) && (res & 0xf) <=  9))
+ 	    res = res + 0xa0;		/* Value added == 0xa0.  */
+ 	  else if (c && (6 <= (res >>  4) && (res >>  4) <= 15) && 
+ 		   h && (6 <= (res & 0xf) && (res & 0xf) <= 15))
+ 	    res = res + 0x9a;		/* Value added == 0x9a.  */
+ 
+ 	  goto alu8;
+ 
  	default:
  	illegal:
  	  cpu.state = SIM_STATE_STOPPED;

Re: [PATCH/RFA] h8300 sim: add daa and das insns

[Kazu Hirata]

Hi Michael,

> Here's my implementation of daa/das:

+ 	  if (!c && (0 <= (res >>  4) && (res >>  4) <= 9) && 
+ 	      !h && (0 <= (res & 0xf) && (res & 0xf) <= 9))

The GNU coding standard says

  if (A
      && B)

so we would have to fix formatting.

+ 	  else if ( c && (1 <= (res >>  4) && (res >>  4) <= 2) && 
+ 		   !h && (0 <= (res & 0xf) && (res & 0xf) <= 9))
+ 	    res = res + 0x60;		/* Value added == 60.  */
+ 	  else if ( c && (1  <= (res >>  4) && (res >>  4) <=  2) && 
+ 		   !h && (10 <= (res & 0xf) && (res & 0xf) <= 15))
+ 	    res = res + 0x66;		/* Value added == 66.  */
+ 	  else if (c && (1 <= (res >>  4) && (res >>  4) <= 3) && 
+ 		   h && (0 <= (res & 0xf) && (res & 0xf) <= 3))
+ 	    res = res + 0x66;		/* Value added == 66.  */

IMHO, for the last three cases of DAA, the carry flag won't be set to
1 because adding 0x66 does not generate a carry.  We can put a hack
like "res |= 0x100;" after "res += 0x66;" or replace "res += 0x66;"
with "res += 0x166;" so that "alu8:" can take care of this, but I
don't know how much you like these. :-)

Thanks,

Kazu Hirata

Re: [PATCH/RFA] h8300 sim: add daa and das insns

[Michael Snyder]

Kazu Hirata wrote:
> 
> Hi Michael,
> 
> > Here's my implementation of daa/das:
> 
> +         if (!c && (0 <= (res >>  4) && (res >>  4) <= 9) &&
> +             !h && (0 <= (res & 0xf) && (res & 0xf) <= 9))
> 
> The GNU coding standard says
> 
>   if (A
>       && B)

Ugh.  I hate it, but OK.  My way scans so much better...

> so we would have to fix formatting.
> 
> +         else if ( c && (1 <= (res >>  4) && (res >>  4) <= 2) &&
> +                  !h && (0 <= (res & 0xf) && (res & 0xf) <= 9))
> +           res = res + 0x60;           /* Value added == 60.  */
> +         else if ( c && (1  <= (res >>  4) && (res >>  4) <=  2) &&
> +                  !h && (10 <= (res & 0xf) && (res & 0xf) <= 15))
> +           res = res + 0x66;           /* Value added == 66.  */
> +         else if (c && (1 <= (res >>  4) && (res >>  4) <= 3) &&
> +                  h && (0 <= (res & 0xf) && (res & 0xf) <= 3))
> +           res = res + 0x66;           /* Value added == 66.  */
> 
> IMHO, for the last three cases of DAA, the carry flag won't be set to
> 1 because adding 0x66 does not generate a carry.  We can put a hack
> like "res |= 0x100;" after "res += 0x66;" or replace "res += 0x66;"
> with "res += 0x166;" so that "alu8:" can take care of this, but I
> don't know how much you like these. :-)

Right you are.  I think your suggestion is both necessary and sufficient.
Sure it's odd, but this is binary coded decimal we're talking about...

I'll check it in with your suggestions.  Thanks.