From d0491186abedd36a6e065e97bf29eaaf87f6f95c Mon Sep 17 00:00:00 2001
From: Andreas Baumann <mail@andreasbaumann.cc>
Date: Fri, 24 Sep 2021 19:07:50 +0000
Subject: cc: about to emulate a printint build-in keyword (for now just prints
 a string)

---
 miniany/REQUIREMENTS |  7 ++++++
 miniany/cc.c         | 67 +++++++++++++++++++++++++++++++++++++++++++++++-----
 miniany/test1.c      |  1 +
 3 files changed, 69 insertions(+), 6 deletions(-)

diff --git a/miniany/REQUIREMENTS b/miniany/REQUIREMENTS
index 7dcfc78..0472c1e 100644
--- a/miniany/REQUIREMENTS
+++ b/miniany/REQUIREMENTS
@@ -110,3 +110,10 @@ TODO:
   - static: just ignore, we don't have a linker, otoh, just rewrite it whithout static,
     vararg, etc.
 - c4.c: checkout c5-AST branch (darn, that one looks more promising to extend!)
+- cc.c: putint as a command in the language for early debugging (as in early Pascal),
+  points to a fundamental conflict: bootstrapping is better with stdout and stdin in
+  the language (no linker, no function calls etc. needed). OTOH we don't want to
+  have I/O as part of the language later, more be in the standard library.
+  Inline assembly in the generated code duplicates code with the putint in libc-freestanding.
+  
+  
diff --git a/miniany/cc.c b/miniany/cc.c
index 4d26893..b9cfe5a 100644
--- a/miniany/cc.c
+++ b/miniany/cc.c
@@ -15,6 +15,7 @@ enum {
 	S_SEMICOLON,
 	S_EQUALS,
 	S_INT = 10,
+	S_PUTINT,
 	S_IDENT = 20,
 	S_NUM = 30,
 	S_EOI = 98,
@@ -155,6 +156,15 @@ int keyword( char *ident )
 				return 0;
 			}
 			break;
+			
+		case 'p':
+			if( strcmp( ident, "putint" ) == 0 ) {
+				return S_PUTINT;
+			} else {
+				return 0;
+			}
+			break;
+			
 		default:
 			return  0;
 	}
@@ -782,12 +792,37 @@ int generateFromAST( struct Generator *generator, struct ASTnode *node, int inre
 
 void genPrologue( struct Compiler *compiler )
 {
-	putstring( "format binary" );
-	putnl( );
-	putstring( "use32" );
-	putnl( );
-	putstring( "org $1000000" );
-	putnl( );
+	putstring( "format binary" ); putnl( );
+	putstring( "use32" ); putnl( );
+	putstring( "org $1000000" ); putnl( );
+	putstring( "jmp _start" ); putnl( );
+	putstring( "putint:" ); putnl( );
+	putstring( "mov eax, 4" ); putnl( );
+	putstring( "mov ebx, 1" ); putnl( );
+	/* TODO: itoa in assembly (yuck!) and print resulting string */
+	putstring( "mov ecx, putint_string" ); putnl( );
+	/* TODO: compute length with a assemble time function sizeof or so.. */
+	putstring( "mov edx, 13" ); putnl( );
+	putstring( "int 0x80" ); putnl( );
+	putstring( "ret 4" ); putnl( );
+	putstring( "_start:" ); putnl( );
+	
+/*
+		__asm__ volatile( "\
+		push %%ebx\n\
+		push %%ecx\n\
+		push %%edx\n\
+		mov %1, %%eax\n\
+		mov %2, %%ebx\n\
+		mov %3, %%ecx\n\
+		mov %4, %%edx\n\
+		int $0x80\n\
+		mov %%eax, %0\n\
+		pop %%edx\n\
+		pop %%ecx\n\
+		pop %%ebx\n" : "=m"( retval ) : "m"( id ), "m"( arg0 ), "m"( arg1 ), "m"( arg2 )
+		: "eax", "ebx", "ecx", "edx" );		
+		*/
 }
 
 void genEpilogue( struct Compiler *compiler )
@@ -801,6 +836,8 @@ void genEpilogue( struct Compiler *compiler )
 		genAddGlob( compiler->generator, sym->name );
 		sym = sym->next;
 	}
+	putstring( "putint_string:" ); putnl( );
+	putstring( "db \"putint test \", 10, 0" ); putnl( );
 }
 
 /* parser */
@@ -1002,6 +1039,22 @@ void parseAssignment( struct Compiler *compiler )
 	freeASTnode( node );
 }
 
+void parsePutint( struct Compiler *compiler )
+{
+	struct Parser *parser;
+	struct ASTnode *node;
+	
+	parser = compiler->parser;
+	parserExpect( parser, S_PUTINT, "putint" );
+	node = parseExpression( parser, 0 );
+	parserExpect( parser, S_SEMICOLON, ";" );
+	generateFromAST( compiler->generator, node, NOREG );
+	putstring( "push eax" ); putnl( );
+	putstring( "call putint" ); putnl( );
+	genFreeAllRegs( compiler->generator );
+	freeASTnode( node );
+}
+
 void parseStatement( struct Compiler *compiler )
 {
 	struct Parser *parser;
@@ -1011,6 +1064,8 @@ void parseStatement( struct Compiler *compiler )
 		parseDeclaration( compiler );
 	} else if( parser->token == S_IDENT ) {
 		parseAssignment( compiler );
+	} else if( parser->token == S_PUTINT ) {
+		parsePutint( compiler );
 	} else if( parser->token == S_EOI ) {
 		return;
 	} else {
diff --git a/miniany/test1.c b/miniany/test1.c
index 4eeffed..d7015e2 100644
--- a/miniany/test1.c
+++ b/miniany/test1.c
@@ -5,3 +5,4 @@ int j;
 
 i = 12+25/5-2*3; // 25/5 -> 5, 12+5 -> 17, 2*3 -> 6, 17-6 -> 11
 j = i/3+3*4; // 11 / 3 -> 3, 3*4 -> 12, 3+12 -> 15 
+putint i;
-- 
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