From 5670654667355c55104386a199a78381e9dad207 Mon Sep 17 00:00:00 2001
From: Yaossg <yaossg@outlook.com>
Date: Sun, 17 Nov 2024 10:52:27 +0800
Subject: [PATCH] do-while

---
 README.md |  2 +-
 boot.c    | 22 +++++++++++++++++++++-
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 9ceab42..649122e 100644
--- a/README.md
+++ b/README.md
@@ -66,7 +66,7 @@ $ sh boot.sh
 ### 支持的流程控制
 
 - `if` `else`
-- `while` `for`
+- `while` `for` `do`
 - `break` `continue`
 - `return`
 
diff --git a/boot.c b/boot.c
index 1c53544..8225237 100644
--- a/boot.c
+++ b/boot.c
@@ -68,6 +68,7 @@ const int TOKEN_VOID = 109;
 const int TOKEN_CONST = 110;
 const int TOKEN_CHAR = 111;
 const int TOKEN_FOR = 112;
+const int TOKEN_DO = 113;
 const int TOKEN_STRING = 150;
 
 int parse_int(int ch) {
@@ -193,6 +194,8 @@ void parse_id_like(int ch) {
         token_type = TOKEN_CHAR;
     } else if (streq(id, "for")) {
         token_type = TOKEN_FOR;
+    } else if (streq(id, "do")) {
+        token_type = TOKEN_DO;
     }
     if (token_type != TOKEN_ID) {
         rewind_id(0);
@@ -249,7 +252,7 @@ void next_token() {
     } else if (ch == '/') {
         int ch2 = getchar();
         if (ch2 == '/') {
-            while ((ch = getchar()) != -1 && ch != '\n');
+            do ch = getchar(); while (ch != -1 && ch != '\n');
             next_token();
             return;
         } else if (ch2 == '*') {
@@ -1174,6 +1177,21 @@ void parse_for() {
     asm_pop_label();
 }
 
+void parse_do_while() {
+    int cont_label = next_label();
+    int break_label = next_label();
+    asm_push_label(break_label, cont_label);
+    asm_label(cont_label);
+    parse_stmt(); // body
+    expect_token(TOKEN_WHILE);
+    expect_token(TOKEN_PAREN_LEFT);
+    int cond = parse_expr();
+    asm_bnez(cond, cont_label);
+    expect_token(TOKEN_PAREN_RIGHT);
+    asm_label(break_label);
+    asm_pop_label();
+}
+
 void parse_stmt() {
     next_token();
     int decl_type;
@@ -1186,6 +1204,8 @@ void parse_stmt() {
     } else if (token_type == TOKEN_FOR) {
         parse_for();
         return;
+    } else if (token_type == TOKEN_DO) {
+        parse_do_while();
     } else if (token_type == TOKEN_BRACE_LEFT) {
         while (1) {
             next_token();