[RFA (revised)] sh-sim, expand the opcode table

[Michael Snyder <msnyder@redhat.com>]

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Hi Joern,

Here are some benchmark results.  Following your advice, I took the
arith-rand test, increased its main loop count until it took around
10 seconds to run on my test machine, and tested it against the eight
optimization combinations that are tested for in the gcc torture test
[see methodology notes attached]


I found that my change increased the runtime by 1.5 to 2 percent
(even when I added the new instructions that I'm working on).
That didn't seem too bad to me, but I took some advice from Alex
Oliva and tried simply changing the sh_jmp_table from char to short.
This much simpler change increased the runtime by only 0.5 to 1
percent, at the cost of 64k more data space.

So I'll withdraw my previous patch and submit the following instead:


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2004-02-10  Michael Snyder  <msnyder@redhat.com>

	* gencode.c (table): Change from char to short.
	(dumptable): Change generated table from char to short.
	* interp.c (sh_jump_table, sh_dsp_table, ppi_table): char to short.
	(init_dsp): Compute size of sh_dsp_table.
	(sim_resume): Change jump_table from char to short.

Index: gencode.c
===================================================================
RCS file: /cvs/src/src/sim/sh/gencode.c,v
retrieving revision 1.26
diff -p -r1.26 gencode.c
*** gencode.c	27 Jan 2004 23:30:01 -0000	1.26
--- gencode.c	11 Feb 2004 00:34:36 -0000
*************** gengastab ()
*** 2265,2271 ****
      }
  }
  
! static unsigned char table[1 << 16];
  
  /* Take an opcode, expand all varying fields in it out and fill all the
     right entries in 'table' with the opcode index.  */
--- 2265,2271 ----
      }
  }
  
! static unsigned short table[1 << 16];
  
  /* Take an opcode, expand all varying fields in it out and fill all the
     right entries in 'table' with the opcode index.  */
*************** dumptable (name, size, start)
*** 2407,2413 ****
  
    int i = start;
  
!   printf ("unsigned char %s[%d]={\n", name, size);
    while (i < start + size)
      {
        int j = 0;
--- 2407,2413 ----
  
    int i = start;
  
!   printf ("unsigned short %s[%d]={\n", name, size);
    while (i < start + size)
      {
        int j = 0;
Index: interp.c
===================================================================
RCS file: /cvs/src/src/sim/sh/interp.c,v
retrieving revision 1.14
diff -p -r1.14 interp.c
*** interp.c	10 Jan 2004 00:43:28 -0000	1.14
--- interp.c	11 Feb 2004 00:34:37 -0000
***************
*** 53,59 ****
  #define SIGTRAP 5
  #endif
  
! extern unsigned char sh_jump_table[], sh_dsp_table[0x1000], ppi_table[];
  
  int sim_write (SIM_DESC sd, SIM_ADDR addr, unsigned char *buffer, int size);
  
--- 53,59 ----
  #define SIGTRAP 5
  #endif
  
! extern unsigned short sh_jump_table[], sh_dsp_table[0x1000], ppi_table[];
  
  int sim_write (SIM_DESC sd, SIM_ADDR addr, unsigned char *buffer, int size);
  
*************** init_dsp (abfd)
*** 1646,1652 ****
      {
        int i, tmp;
  
!       for (i = sizeof sh_dsp_table - 1; i >= 0; i--)
  	{
  	  tmp = sh_jump_table[0xf000 + i];
  	  sh_jump_table[0xf000 + i] = sh_dsp_table[i];
--- 1646,1652 ----
      {
        int i, tmp;
  
!       for (i = (sizeof sh_dsp_table / sizeof sh_dsp_table[0]) - 1; i >= 0; i--)
  	{
  	  tmp = sh_jump_table[0xf000 + i];
  	  sh_jump_table[0xf000 + i] = sh_dsp_table[i];
*************** sim_resume (sd, step, siggnal)
*** 1752,1758 ****
    void (*prev) ();
    void (*prev_fpe) ();
  
!   register unsigned char *jump_table = sh_jump_table;
  
    register int *R = &(saved_state.asregs.regs[0]);
    /*register int T;*/
--- 1752,1758 ----
    void (*prev) ();
    void (*prev_fpe) ();
  
!   register unsigned short *jump_table = sh_jump_table;
  
    register int *R = &(saved_state.asregs.regs[0]);
    /*register int T;*/

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Benchmark Methodology Notes:

Dell Precision 420 running RH 7.3 
No other users, no other user processes except X and windows manager.
Main loop increased from 1000 to 100000 iterations.
Each test run 3 times and averaged.

Time in seconds for control, 16-bit table, and split table, 
with percent increase.  "omit" == -fomit-frame-pointer, 
"unroll" == -funroll-all-loops.

		ctrl	2table	%inc	16bit	%inc

O0		10.862	11.044	1.7	10.884	.20
		10.855	11.040	1.7	10.875	.18
O1		6.669	6.810	2.1	6.700	.46
		6.660	6.805	2.2	6.700	.60
O2		6.561	6.707	2.2	6.650	1.36
		6.555	6.710	2.4	6.650	1.45
O3		5.780	5.876	1.7	5.800	.34
		5.780	5.875	1.6	5.800	.34
O3 omit		5.646	5.744	1.7	5.671	.44
		5.640	5.740	1.8	5.670	.53
O3 omit unroll	5.636	5.744	1.9	5.664	.50
		5.630	5.750	2.1	5.660	.53
O3 -g		5.772	5.875	1.8	5.799	.46
		5.770	5.865	1.6	5.795	.43
Os		6.600	6.735	2.0	6.649	.74
		6.590	6.730	2.1	6.650	.91