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#include "codegen.h"
#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include "ast.h"
static void gencondjmp(FILE *f, cond_t *c, bool neg)
{
uint8_t cmp = neg ? c->cmp^0x80 : c->cmp;
fprintf(f, "cmp %s %s\n", c->a, c->b);
switch (cmp) {
case CEQ:
fprintf(f, "je ");
break;
case CNEQ:
fprintf(f, "jne ");
break;
case CGT:
fprintf(f, "jg ");
break;
case CLT:
fprintf(f, "jl ");
break;
case CLEQ:
fprintf(f, "jle ");
break;
case CGEQ:
fprintf(f, "jge ");
break;
default:
fprintf(stderr, "Invalid cmp type %x", cmp);
fprintf(f, "jmp ");
}
}
static void genif(FILE *f, struct genctx *ctx, ast_node_t *n)
{
bool doElse = n->flowctrl.iffalse;
// Create conditional jump
gencondjmp(f, n->flowctrl.condition, true);
if ( doElse ) {
fprintf(f, "else_%d\n", ctx->nested);
} else {
fprintf(f, "end_%d\n", ctx->nested);
}
struct genctx octx = { ctx->nested+1 };
// Paste code
gentree(f, &octx, n->flowctrl.iftrue);
// Do else
if ( doElse ) {
fprintf(f, "jmp end_%d\n", ctx->nested);
fprintf(f, "else_%d:\n", ctx->nested);
gentree(f, &octx, n->flowctrl.iffalse);
}
// End block
fprintf(f, "end_%d:\n", ctx->nested);
}
static void genwhile(FILE *f, struct genctx *ctx, ast_node_t *n)
{
// Create loop label
fprintf(f, "loop_%d:\n", ctx->nested);
// Create conditional jump
gencondjmp(f, n->flowctrl.condition, true);
fprintf(f, "end_%d\n", ctx->nested);
struct genctx octx = { ctx->nested+1 };
// Paste code
gentree(f, &octx, n->flowctrl.iftrue);
// Jump to start
fprintf(f, "jmp loop_%d\n", ctx->nested);
// End block
fprintf(f, "end_%d:\n", ctx->nested);
}
static void genfor(FILE *f, struct genctx *ctx, ast_node_t *n)
{
// Do pre stuff
fprintf(f, "%s\n", n->forloop.pre);
// Create loop label
fprintf(f, "loop_%d:\n", ctx->nested);
// Create conditional jump
gencondjmp(f, n->flowctrl.condition, true);
fprintf(f, "end_%d\n", ctx->nested);
struct genctx octx = { ctx->nested+1 };
// Paste code
gentree(f, &octx, n->forloop.stuff);
// Do inc stuff
fprintf(f, "%s\n", n->forloop.inc);
// Jump to start
fprintf(f, "jmp loop_%d\n", ctx->nested);
// End block
fprintf(f, "end_%d:\n", ctx->nested);
}
void gentree(FILE *f, struct genctx *ctx, ast_node_t *n)
{
if ( !n ) {
return;
}
if ( ctx == NULL ) {
ctx = malloc(sizeof(struct genctx));
ctx->nested = 0;
}
switch (n->t) {
case TSTM_LIST:
gentree(f, ctx, n->list.children[0]);
gentree(f, ctx, n->list.children[1]);
break;
case TIF:
genif(f, ctx, n);
break;
case TIDENT:
fprintf(f, "%s\n", n->ident);
break;
case TFOR:
genfor(f, ctx, n);
break;
case TWHILE:
genwhile(f, ctx, n);
break;
default:
return;
}
}
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