added Josh's dynamic display assembly generator

This commit is contained in:
Brian Paul
2000-01-31 22:51:44 +00:00
parent 4df415b190
commit 4428a3f359

View File

@@ -1,4 +1,4 @@
/* $Id: glapi.c,v 1.29 2000/01/28 20:17:42 brianp Exp $ */
/* $Id: glapi.c,v 1.30 2000/01/31 22:51:44 brianp Exp $ */
/*
* Mesa 3-D graphics library
@@ -299,13 +299,51 @@ static GLuint NumExtEntryPoints = 0;
/*
* Generate a dispatch function (entrypoint) which jumps through
* the given slot number (offset) in the current dispatch table.
* We need assembly language in order to accomplish this.
*/
static void *
generate_entrypoint(GLuint offset)
{
/* XXX need to generate some assembly code here */
#if defined(USE_X86_ASM)
/*
* This x86 code contributed by Josh Vanderhoof.
*
* 0: a1 10 32 54 76 movl __glapi_Dispatch,%eax
* 00 01 02 03 04
* 5: 85 c0 testl %eax,%eax
* 05 06
* 7: 74 06 je f <entrypoint+0xf>
* 07 08
* 9: ff a0 10 32 54 76 jmp *0x76543210(%eax)
* 09 0a 0b 0c 0d 0e
* f: e8 fc ff ff ff call __glapi_get_dispatch
* 0f 10 11 12 13
* 14: ff a0 10 32 54 76 jmp *0x76543210(%eax)
* 14 15 16 17 18 19
*/
static const unsigned char temp[] = {
0xa1, 0x00, 0x00, 0x00, 0x00,
0x85, 0xc0,
0x74, 0x06,
0xff, 0xa0, 0x00, 0x00, 0x00, 0x00,
0xe8, 0x00, 0x00, 0x00, 0x00,
0xff, 0xa0, 0x00, 0x00, 0x00, 0x00
};
unsigned char *code = malloc(sizeof(temp));
unsigned int next_insn;
if (code) {
memcpy(code, temp, sizeof(temp));
*(unsigned int *)(code + 0x01) = (unsigned int)&_glapi_Dispatch;
*(unsigned int *)(code + 0x0b) = (unsigned int)functionOffset * 4;
next_insn = (unsigned int)(code + 0x14);
*(unsigned int *)(code + 0x10) = (unsigned int)_glapi_get_dispatch - next_insn;
*(unsigned int *)(code + 0x16) = (unsigned int)functionOffset * 4;
}
return code;
#else
return NULL;
#endif
}