BizHawk/waterbox/ares64/ares/thirdparty/sljit/doc/tutorial/loop.c

77 lines
1.6 KiB
C

#include "sljitLir.h"
#include <stdio.h>
#include <stdlib.h>
typedef long (SLJIT_FUNC *func2_t)(long a, long b);
/*
This example, we generate a function like this:
long func(long a, long b)
{
long i;
long ret = 0;
for (i = 0; i < a; ++i) {
ret += b;
}
return ret;
}
*/
static int loop(long a, long b)
{
void *code;
unsigned long len;
func2_t func;
struct sljit_label *loopstart;
struct sljit_jump *out;
/* Create a SLJIT compiler */
struct sljit_compiler *C = sljit_create_compiler(NULL, NULL);
/* 2 arg, 2 temp reg, 2 saved reg */
sljit_emit_enter(C, 0, SLJIT_ARGS2(W, W, W), 2, 2, 0, 0, 0);
/* R0 = 0 */
sljit_emit_op2(C, SLJIT_XOR, SLJIT_R1, 0, SLJIT_R1, 0, SLJIT_R1, 0);
/* RET = 0 */
sljit_emit_op1(C, SLJIT_MOV, SLJIT_RETURN_REG, 0, SLJIT_IMM, 0);
/* loopstart: */
loopstart = sljit_emit_label(C);
/* R1 >= a --> jump out */
out = sljit_emit_cmp(C, SLJIT_GREATER_EQUAL, SLJIT_R1, 0, SLJIT_S0, 0);
/* RET += b */
sljit_emit_op2(C, SLJIT_ADD, SLJIT_RETURN_REG, 0, SLJIT_RETURN_REG, 0, SLJIT_S1, 0);
/* R1 += 1 */
sljit_emit_op2(C, SLJIT_ADD, SLJIT_R1, 0, SLJIT_R1, 0, SLJIT_IMM, 1);
/* jump loopstart */
sljit_set_label(sljit_emit_jump(C, SLJIT_JUMP), loopstart);
/* out: */
sljit_set_label(out, sljit_emit_label(C));
/* return RET */
sljit_emit_return(C, SLJIT_MOV, SLJIT_RETURN_REG, 0);
/* Generate machine code */
code = sljit_generate_code(C);
len = sljit_get_generated_code_size(C);
/* Execute code */
func = (func2_t)code;
printf("func return %ld\n", func(a, b));
/* dump_code(code, len); */
/* Clean up */
sljit_free_compiler(C);
sljit_free_code(code, NULL);
return 0;
}
int main()
{
return loop(4, 5);
}