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#include <stdio.h>
#include <lightning.h>
static jit_state_t *_jit;
typedef long (*pwfw_t)(long); /* Pointer to Long Function of Long */
int main(int argc, char *argv[])
{
pwfw_t factorial;
long arg;
jit_node_t *ac; /* Accumulator */
jit_node_t *in; /* Argument */
jit_node_t *call;
jit_node_t *fact;
jit_node_t *jump;
jit_node_t *fact_entry;
jit_node_t *fact_out;
init_jit(argv[0]);
_jit = jit_new_state();
/* declare a forward label */
fact = jit_forward();
jit_prolog(); /* Entry point of the factorial function */
in = jit_arg(); /* Receive an integer argument */
jit_getarg(JIT_R0, in); /* Move argument to RO */
jit_prepare();
jit_pushargi(1); /* This is the accumulator */
jit_pushargr(JIT_R0); /* This is the argument */
call = jit_finishi(NULL); /* Call the tail call optimized function */
jit_patch_at(call, fact); /* Patch call to forward defined function */
/* the above could have been written as:
* jit_patch_at(jit_finishi(NULL), fact);
*/
jit_retval(JIT_R0); /* Fetch the result */
jit_retr(JIT_R0); /* Return it */
jit_epilog(); /* Epilog *before* label before prolog */
/* define the forward label */
jit_link(fact); /* Entry point of the helper function */
jit_prolog();
jit_frame(16); /* Reserve 16 bytes in the stack */
fact_entry = jit_label(); /* This is the tail call entry point */
ac = jit_arg(); /* The accumulator is the first argument */
in = jit_arg(); /* The factorial argument */
jit_getarg(JIT_R0, ac); /* Move the accumulator to R0 */
jit_getarg(JIT_R1, in); /* Move the argument to R1 */
fact_out = jit_blei(JIT_R1, 1); /* Done if argument is one or less */
jit_mulr(JIT_R0, JIT_R0, JIT_R1); /* accumulator *= argument */
jit_putargr(JIT_R0, ac); /* Update the accumulator */
jit_subi(JIT_R1, JIT_R1, 1); /* argument -= 1 */
jit_putargr(JIT_R1, in); /* Update the argument */
jump = jit_jmpi();
jit_patch_at(jump, fact_entry); /* Tail Call Optimize it! */
jit_patch(fact_out);
jit_retr(JIT_R0); /* Return the accumulator */
factorial = jit_emit();
/* no need to query information about resolved addresses */
jit_clear_state();
if (argc == 2)
arg = atoi(argv[1]);
else
arg = 5;
/* call the generated code */
printf("factorial(%ld) = %ld\n", arg, factorial(arg));
/* release all memory associated with the _jit identifier */
jit_destroy_state();
finish_jit();
return 0;
}
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