[hatari-devel] Strange CPU cycles
Laurent Sallafranque
laurent.sallafranque at free.fr
Tue Feb 23 13:01:42 CET 2010
Hello,
I've added the following spy in the code :
/**
* Run DSP for certain cycles
*/
void DSP_Run(int nHostCycles)
{
#if ENABLE_DSP_EMU
/* Cycles emulation is just a rough approximation by now.
* (to be tuned ...) */
int i = nHostCycles * 2 + 2;
int dsp_cycle = 0;
if (i > 50)
fprintf(stderr, "%d i\n", i);
...
I've started a demo. From Falcon boot to demo running ,I've got many
68030 instructions that are > 50 cycles :
...
86 i
86 i
258 i
82 i
54 i
274 i
82 i
54 i
262 i
82 i
54 i
270 i
82 i
54 i
270 i
...
This is just a small copy of what I get in real.
How is it possible that a 68030 takes 258 cycles ?
As DSP code and crossbar code are relative to CPU cycles, it looks
strange for me.
Regards,
Laurent
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