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Revert "Optimize vswap()"

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This reverts commit 63193d1794.

Had some problems (_STATIC_ASSERT) and was too ugly anyway.
For retry, I'd suggest to implement a general function
    static inline void memswap (void *p1, void* p2, size_t n);
and then use that.  If you do so, please keep the original code
as comment.
This commit is contained in:
grischka 2013-01-14 18:33:59 +01:00
parent 2daf8b96a8
commit c5892fe4f5
2 changed files with 8 additions and 33 deletions
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4
tcc.h
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@ -228,10 +228,6 @@
#define true 1 #define true 1
typedef int BOOL; typedef int BOOL;
#ifndef _STATIC_ASSERT
#define _STATIC_ASSERT(cond) do { (void) sizeof(char [1 - 2*!(cond)]); } while(0)
#endif
#define INCLUDE_STACK_SIZE 32 #define INCLUDE_STACK_SIZE 32
#define IFDEF_STACK_SIZE 64 #define IFDEF_STACK_SIZE 64
#define VSTACK_SIZE 256 #define VSTACK_SIZE 256

37
tccgen.c
View file

@ -458,7 +458,7 @@ static void vseti(int r, int v)
ST_FUNC void vswap(void) ST_FUNC void vswap(void)
{ {
unsigned long *vtopl; SValue tmp;
/* cannot let cpu flags if other instruction are generated. Also /* cannot let cpu flags if other instruction are generated. Also
avoid leaving VT_JMP anywhere except on the top of the stack avoid leaving VT_JMP anywhere except on the top of the stack
because it would complicate the code generator. */ because it would complicate the code generator. */
@ -467,35 +467,14 @@ ST_FUNC void vswap(void)
if (v == VT_CMP || (v & ~1) == VT_JMP) if (v == VT_CMP || (v & ~1) == VT_JMP)
gv(RC_INT); gv(RC_INT);
} }
tmp = vtop[0];
vtop[0] = vtop[-1];
vtop[-1] = tmp;
/* /* XXX: +2% overall speed possible with optimized memswap
* vtop[0], vtop[-1] = vtop[-1], vtop[0] *
* * memswap(&vtop[0], &vtop[1], sizeof *vtop);
* vswap is called often and exchanging vtop[0] vs vtop[-1] is hot on */
* profile, so it is hand optimized
*/
vtopl = (unsigned long *) vtop;
# define VSIZEL (sizeof(*vtop) / sizeof(*vtopl))
_STATIC_ASSERT( VSIZEL*sizeof(*vtopl) == sizeof(*vtop) );
_STATIC_ASSERT( VSIZEL <= 16 ); /* should be enough */
switch(VSIZEL) {
# define VSWAPL(i) \
case i+1: { \
unsigned long tmpl; \
tmpl = vtopl[i]; \
vtopl[i] = vtopl[-1*VSIZEL + i]; \
vtopl[-1*VSIZEL + i] = tmpl; \
} do {} while (0)
VSWAPL(15); VSWAPL(14); VSWAPL(13); VSWAPL(12);
VSWAPL(11); VSWAPL(10); VSWAPL( 9); VSWAPL( 8);
VSWAPL( 7); VSWAPL( 6); VSWAPL( 5); VSWAPL( 4);
VSWAPL( 3); VSWAPL( 2); VSWAPL( 1); VSWAPL( 0);
}
# undef VSWAPL
# undef VSIZEL
} }
ST_FUNC void vpushv(SValue *v) ST_FUNC void vpushv(SValue *v)