codegen.c

#include <stdio.h>
#include "9cc.h"

void gen_lval(Node *node) {
    if (node->kind != ND_LVAR)
        error("代入の左辺値が変数ではありません");

    printf("  mov rax, rbp\n");
    printf("  sub rax, %d\n", node->offset);
    printf("  push rax\n");
}

void gen(Node *node) {
    if (node->kind == ND_RETURN) {
        gen(node->lhs);
        printf("  pop rax\n");
        printf("  mov rsp, rbp\n");
        printf("  pop rbp\n");
        printf("  ret\n");
        return;
    }
    switch (node->kind) {
    case ND_NUM:
        printf("   push %d\n", node->val);
        return;
    case ND_LVAR:
        gen_lval(node);
        printf("  pop rax\n");
        printf("  mov rax, [rax]\n");
        printf("  push rax\n");
        return;
    case ND_ASSIGN:
        gen_lval(node->lhs);
        gen(node->rhs);

        printf("  pop rdi\n");
        printf("  pop rax\n");
        printf("  mov [rax], rdi\n");
        printf("  push rdi\n");
        return;
    }


    gen(node->lhs);
    gen(node->rhs);

    printf("  pop rdi\n");
    printf("  pop rax\n");

    switch (node->kind) {
    case ND_ADD:
        printf("  add rax, rdi\n");
        break;
    case ND_SUB:
        printf("  sub rax, rdi\n");
        break;
    case ND_MUL:
        printf("  imul rax, rdi\n");
        break;
    case ND_DIV:
        printf("  cqo\n");
        printf("  idiv rdi\n");
        break;
    case ND_EQ:
        printf("  cmp rax, rdi\n");
        printf("  sete al\n");
        printf("  movzb rax, al\n");
        break;
    case ND_NE:
        printf("  cmp rax, rdi\n");
        printf("  setne al\n");
        printf("  movzb rax, al\n");
        break;
    case ND_GT:
        printf("  cmp rax, rdi\n");
        printf("  setg al\n");
        printf("  movzb rax, al\n");
        break;
    case ND_GE:
        printf("  cmp rax, rdi\n");
        printf("  setge al\n");
        printf("  movzb rax, al\n");
        break;
    case ND_LT:
        printf("  cmp rax, rdi\n");
        printf("  setl al\n");
        printf("  movzb rax, al\n");
        break;
    case ND_LE:
        printf("  cmp rax, rdi\n");
        printf("  setle al\n");
        printf("  movzb rax, al\n");
        break;
    }

    printf("  push rax\n");
}