From 62924274b391dbfd16f4349bd46a2136f2a78b0e Mon Sep 17 00:00:00 2001
From: Andreas Baumann <mail@andreasbaumann.cc>
Date: Wed, 13 Oct 2021 20:32:29 +0200
Subject: cc: some support for putchar and char store/load

---
 miniany/cc.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 53 insertions(+), 9 deletions(-)

(limited to 'miniany/cc.c')

diff --git a/miniany/cc.c b/miniany/cc.c
index e977bc9..c72d290 100644
--- a/miniany/cc.c
+++ b/miniany/cc.c
@@ -32,6 +32,7 @@ enum {
 	S_WHILE,
 	S_DO,
 	S_PUTINT,
+	S_PUTCHAR,
 	S_IDENT = 60,
 	S_NUM = 70,
 	S_EOI = 98,
@@ -194,6 +195,8 @@ int keyword( char *ident )
 		case 'p':
 			if( strcmp( ident, "putint" ) == 0 ) {
 				return S_PUTINT;
+			} else if( strcmp( ident, "putchar" ) == 0 ) {
+				return S_PUTCHAR;
 			}
 			break;
 		
@@ -599,7 +602,7 @@ void putlow8reg( struct Generator *generator, int reg )
 			break;
 		default:
 			scannerPrintErrorHeader( generator->scanner );
-			putstring( "error using low 8-bit subreguster of reguster '" );
+			putstring( "error using low 8-bit subreguster of register '" );
 			putstring( generator->regName[reg] );
 			putstring( "'" );
 			putnl( );
@@ -739,27 +742,41 @@ int genLoadImm( struct Generator *generator, int intval )
 	return reg;
 }
 
-int genLoadIdent( struct Generator *generator, char *ident )
+int genLoadIdent( struct Generator *generator, struct Symbol *sym )
 {
 	int reg;
 	
 	reg = genAllocReg( generator );
 	putstring( "mov " );
-	putreg( generator, reg );
+	switch( sym->type ) {
+		case S_INT:
+			putreg( generator, reg );
+			break;
+		case S_CHAR:
+			putlow8reg( generator, reg );
+			break;
+	}
 	putstring( ", [" );
-	putstring( ident );
+	putstring( sym->name );
 	putstring( "]" );
 	putnl( );
 	
 	return reg;
 }
 
-int genStoreIdent( struct Generator *generator, int reg, char *ident )
+int genStoreIdent( struct Generator *generator, int reg, struct Symbol *sym )
 {
 	putstring( "mov [" );
-	putstring( ident );
+	putstring( sym->name );
 	putstring( "], " );
-	putreg( generator, reg );
+	switch( sym->type ) {
+		case S_INT:
+			putreg( generator, reg );
+			break;
+		case S_CHAR:
+			putlow8reg( generator, reg );
+			break;
+	}
 	putnl( );
 	
 	return reg;
@@ -921,10 +938,10 @@ int generateFromAST( struct Generator *generator, struct ASTnode *node, int inre
 			reg = genLoadImm( generator, node->intval );
 			break;
 		case A_IDENT:
-			reg = genLoadIdent( generator, node->sym->name );
+			reg = genLoadIdent( generator, node->sym );
 			break;
 		case A_LVIDENT:
-			reg = genStoreIdent( generator, inreg, node->sym->name );
+			reg = genStoreIdent( generator, inreg, node->sym );
 			break;
 		case A_ADD:
 			reg = genAdd( generator, leftreg, rightreg );
@@ -979,6 +996,14 @@ void genPrologue( struct Compiler *compiler )
 	putstring( "use32" ); putnl( );
 	putstring( "org $1000000" ); putnl( );
 	putstring( "jmp _start" ); putnl( );	
+	putstring( "putchar:" ); putnl( );
+	putstring( "mov [putint_string_fmt], eax" ); putnl( );
+	putstring( "mov eax, 4" ); putnl( );
+	putstring( "mov ebx, 1" ); putnl( );
+	putstring( "mov ecx, putint_string_fmt" ); putnl( );
+	putstring( "mov edx, 1" ); putnl( );
+	putstring( "int 0x80" ); putnl( );
+	putstring( "ret" ); putnl( );
 	putstring( "putint:" ); putnl( );
 	putstring( "mov esi, 0" ); putnl( );
 	putstring( "lea edi, [putint_string_fmt]" ); putnl( );
@@ -1301,6 +1326,23 @@ void parsePutint( struct Compiler *compiler )
 	freeASTnode( node );
 }
 
+void parsePutchar( struct Compiler *compiler )
+{
+	struct Parser *parser;
+	struct ASTnode *node;
+	
+	parser = compiler->parser;
+	parserExpect( parser, S_PUTCHAR, "putchar" );
+	parserExpect( parser, S_LPAREN, "(" );
+	node = parseExpression( parser, 0 );
+	parserExpect( parser, S_RPAREN, ")" );
+	parserExpect( parser, S_SEMICOLON, ";" );
+	generateFromAST( compiler->generator, node, NOREG );
+	putstring( "call putchar" ); putnl( );
+	genFreeAllRegs( compiler->generator );
+	freeASTnode( node );
+}
+
 /* TODO c4: forward reference of function */
 void parseStatementBlock( struct Compiler *compiler );
 
@@ -1437,6 +1479,8 @@ void parseStatement( struct Compiler *compiler )
 		parseAssignment( compiler );
 	} else if( parser->token == S_PUTINT ) {
 		parsePutint( compiler );
+	} else if( parser->token == S_PUTCHAR ) {
+		parsePutchar( compiler );
 	} else if( parser->token == S_IF ) {
 		parseIf( compiler );
 	} else if( parser->token == S_WHILE ) {
-- 
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