From 2e707c4702a06bbe6f44efc732820f6eacce27f9 Mon Sep 17 00:00:00 2001
From: Andreas Baumann <mail@andreasbaumann.cc>
Date: Thu, 30 Sep 2021 13:39:22 +0200
Subject: cc: added do while

---
 miniany/REQUIREMENTS |  6 +++++-
 miniany/cc.c         | 49 +++++++++++++++++++++++++++++++++++++++++++++++--
 miniany/test1.c      |  7 ++++++-
 3 files changed, 58 insertions(+), 4 deletions(-)

diff --git a/miniany/REQUIREMENTS b/miniany/REQUIREMENTS
index cbee3f2..985def7 100644
--- a/miniany/REQUIREMENTS
+++ b/miniany/REQUIREMENTS
@@ -126,5 +126,9 @@ TODO:
       a variable. Knowing the contest would require an AST.
   - AST should not be the output of whole programs, scoping is maybe better
 - don't allow non-blocked if/else, just avoid dangling else problems
-
+- for loops: they simply have a too general and weird semantic in C (missing
+  semicolon after the last triplet). IMHO a for loop makes sense for SIMD
+  operations only when we can use a stricter grammar to optimize certain
+  iterations.
+  
   
diff --git a/miniany/cc.c b/miniany/cc.c
index 6e3f391..cef1af2 100644
--- a/miniany/cc.c
+++ b/miniany/cc.c
@@ -28,6 +28,7 @@ enum {
 	S_IF,
 	S_ELSE,
 	S_WHILE,
+	S_DO,
 	S_PUTINT,
 	S_IDENT = 60,
 	S_NUM = 70,
@@ -162,11 +163,15 @@ void scanIdent( struct Scanner *scanner )
 int keyword( char *ident )
 {
 	switch( ident[0] ) {
+		case 'd':
+			if( strcmp( ident, "do" ) == 0 ) {
+				return S_DO;
+			}
+			break;		
+		
 		case 'e':
 			if( strcmp( ident, "else" ) == 0 ) {
 				return S_ELSE;
-			} else {
-				return 0;
 			}
 			break;
 			
@@ -1329,6 +1334,44 @@ void parseWhile( struct Compiler *compiler )
 	free( label1 );
 }
 
+void parseDo( struct Compiler *compiler )
+{
+	struct Parser *parser;
+	struct ASTnode *node;
+	char *label1;
+
+	parser = compiler->parser;
+	parserExpect( parser, S_DO, "do" );
+	if( compiler->generator->debug ) {
+		putstring( "; do" ); putnl( );
+	}
+	label1 = genGetLabel( compiler, compiler->parser->global_scope );
+	putstring( label1 ); putchar( ':' ); putnl( );
+	parseStatementBlock( compiler );
+	parserExpect( parser, S_WHILE, "while" );
+	parserExpect( parser, S_LPAREN, "(" );
+	node = parseExpression( parser, 0 );
+	generateFromAST( compiler->generator, node, NOREG );
+	putstring( "cmp al, 0" ); putnl( );
+	putstring( "jne " ); putstring( label1 ); putnl( );
+	genFreeAllRegs( compiler->generator );
+	parserExpect( parser, S_RPAREN, ")" );
+	parserExpect( parser, S_SEMICOLON, ";" );
+	free( label1 );
+}
+
+/*
+
+
+	putstring( "jmp " ); putstring( label2 ); putnl( );
+	putstring( label1 ); putchar( ':' ); putnl( );
+	if( compiler->generator->debug ) {
+		putstring( "; fi" ); putnl( );
+	}
+	free( label2 );
+	free( label1 );
+}
+ */
 void parseStatement( struct Compiler *compiler )
 {
 	struct Parser *parser;
@@ -1344,6 +1387,8 @@ void parseStatement( struct Compiler *compiler )
 		parseIf( compiler );
 	} else if( parser->token == S_WHILE ) {
 		parseWhile( compiler );
+	} else if( parser->token == S_DO ) {
+		parseDo( compiler );
 	} else if( parser->token == S_RBRACE || parser->token == S_EOI ) {
 		return;
 	} else {
diff --git a/miniany/test1.c b/miniany/test1.c
index 4492d4f..4bf86e3 100644
--- a/miniany/test1.c
+++ b/miniany/test1.c
@@ -26,9 +26,14 @@
 			putint( 0 );
 		}
 	}
-	i = 10;
+	i = 5;
 	while( i > 0 ) {
 		putint( i );
 		i = i-1;
 	}
+	i = 1;
+	do {
+		putint( i );
+		i = i+1;
+	} while( i <= 5 );
 }
-- 
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