emul.c

  - do not initialize memory (we have constants in the initialized data section!)
  - use last 'hlt' instruction as a separator between code and data

1 files changed, 36 insertions, 18 deletions

diff --git a/ecomp-c/emul.c b/ecomp-c/emul.c
index db63bc2..292002e 100644
--- a/ecomp-c/emul.c
+++ b/ecomp-c/emul.c
@@ -68,15 +68,15 @@ static void dump_stack( uc_engine *uc )
 	}
 }
 
-static void initialize_memory( uc_engine *uc, uint64_t start_address, uint64_t end_address )
-{
-	uint8_t mem[4];
+//~ static void initialize_memory( uc_engine *uc, uint64_t start_address, uint64_t end_address )
+//~ {
+	//~ uint8_t mem[4];
 
-	memset( mem, 0, 4 );
-	for( uint64_t a = start_address; a < end_address; a += 4 ) {
-		uc_mem_write( uc, a, &mem, 4 );
-	}
-}
+	//~ memset( mem, 0, 4 );
+	//~ for( uint64_t a = start_address; a < end_address; a += 4 ) {
+		//~ uc_mem_write( uc, a, &mem, 4 );
+	//~ }
+//~ }
 
 static void dump_memory( uc_engine *uc, uint64_t start_address, uint64_t end_address )
 {
@@ -211,14 +211,32 @@ int main( int argc, char *argv[] )
 		for( int j = ( 16 - instrs[i].size ) * 2; j > 0; j-- ) {
 			printf( " " );
 		}
-		if( instrs[i].size == 2 && instrs[i].bytes[0] == 0 && instrs[i].bytes[1] == 0 ) {
-			if( data_start == 0 ) {
-				data_start = instrs[i].address;
-			}
-			printf( "data\n" );
-		} else {
+
+		if( data_start == 0 ) {
 			printf( "%s %s\n", instrs[i].mnemonic, instrs[i].op_str );
+		} else {
+			printf( "data\n" );
 		}
+
+		/* code and data segment are separated by a 'hlt' instruction,
+		 * 'hlt' must not occur anywhere else and 'hlt' must be the
+		 * last instruction in the code segment.
+		 * Then we can calculate the beginning of the data segment
+		 * (this is all needed as we have a flat binary format only)
+		 */
+		if( strcmp( instrs[i].mnemonic, "hlt" ) == 0 ) {
+			data_start = instrs[i].address + instrs[i].size;
+		}
+		
+		//~ }
+		//~ if( instrs[i].size == 2 && instrs[i].bytes[0] == 0 && instrs[i].bytes[1] == 0 ) {
+			//~ if( data_start == 0 ) {
+				//~ data_start = instrs[i].address;
+			//~ }
+			//~ exit( 1 );
+			//~ printf( "data\n" );
+		//~ } else {
+		//~ }
 	}
 	
 	// remember address to instrs indexes so we can get the current
@@ -263,10 +281,10 @@ int main( int argc, char *argv[] )
 	}
 	
 	// initialize memory (to make tests deterministic)
-	if( data_start == 0 ) {
-		data_start = CODE_START + code_size;
-	}
-	initialize_memory( uc, data_start, data_start + DATA_SIZE );
+	//~ if( data_start == 0 ) {
+		//~ data_start = CODE_START + code_size;
+	//~ }
+	//~ initialize_memory( uc, data_start, data_start + DATA_SIZE );
 	
 	// initialize stack pointer
 	int addr = CODE_START;