ASM: Added support for labels in the assembler

assembly.c

@@ -3,6 +3,8 @@
 #include <stdlib.h>
 #include <stdio.h>
 
+#define MAX_LABEL_SIZE 30
+#define MAX_LABEL_SIZE_str "30"
 
 // Max instruction width is 25 characters without the null char
 //
@@ -208,8 +210,36 @@ char *disassemble(uint32_t opcode_be){
 	return ret;
 }
 
+int32_t parse_immediate(char* str,struct assembler_context_t *assembler_context){
+	if(*str=='0'){
+		uint32_t addr;
+		if(sscanf(str,"%06X",&addr)!=1)
+			return -1;
+		else
+			return addr&0x00FFFFFF;
+	}else{
+		// Get name size
+		int len=0;
+		for(int i=0;i<MAX_LABEL_SIZE+1;i++){
+			if(i==MAX_LABEL_SIZE)
+				return -2;
+			if(str[i]==0||str[i]=='\n'||str[i]==' '){
+					break;
+			}else
+					len++;
+		}
 
-uint32_t assemble_line(char *line, __attribute__((unused)) struct assembler_context_t *assembler_context){
+		struct label_ll_t *search=assembler_context->label_ll;
+		while(search){
+			if(strncmp(str,search->name,len)==0)
+				return search->address;
+			search=search->next;
+		}
+		return -2;
+	}
+}
+
+uint32_t assemble_line(char *line, struct assembler_context_t *assembler_context){
 	uint16_t opcode;
 	int x;
 	int call;
@@ -246,13 +276,18 @@ uint32_t assemble_line(char *line, __attribute__((unused)) struct assembler_cont
 		}else
 			return 0xFFFFFFFF;
 		while(line[x]==' ')x++;
-		uint32_t addr;
 		if(line[x]=='$'){
 			x++;
-			if(sscanf(line+x,"%06X",&addr)!=1)
+			int32_t imm=parse_immediate(line+x,assembler_context);
+			if(imm<0){
+				switch(imm){
+					default:
 						return 0xFFFFFFFF;
-			else
-				return opcode<<24|(addr&0x00FFFFFF);
+					case -2:
+						return 0xFFFFFFFE;
+				}
+			}else
+				return opcode<<24|(imm&0x00FFFFFF);
 		}else
 			return 0xFFFFFFFF;
 	}else{
@@ -372,11 +407,54 @@ uint32_t assemble_line(char *line, __attribute__((unused)) struct assembler_cont
 				return 0xFFFFFFFF;
 		}else if(strncmp(line,"RET",3)==0){
 			return 0x10000000;
-		}
+		}else if(*line==':')
+			return 0xFFFFFFF0;
 		return 0xFFFFFFFF;
 	}
 }
 
+int assembler_context_process(char* line,struct assembler_context_t *assembler_context){
+	switch(line[0]){
+		case ':':
+			if(line[1]==0)
+				return 1;
+			else{
+				char* label=malloc(MAX_LABEL_SIZE+1);
+				sscanf(line+1,"%"MAX_LABEL_SIZE_str"s",label);
+				struct label_ll_t **current;
+				current=&(assembler_context->label_ll);
+				while(*current)
+					current=&((*current)->next);
+				*current=malloc(sizeof(struct label_ll_t));
+				(*current)->name=label;
+				(*current)->address=assembler_context->current_location;
+				(*current)->next=NULL;
+			}
+			break;
+		case 0:
+			return 0;
+		default:
+			assembler_context->current_location+=4;
+
+	}
+	return 0;
+}
+
+struct assembler_context_t *malloc_assembler_context(){
+	struct assembler_context_t *ret;
+	ret=malloc(sizeof(struct assembler_context_t));
+	ret->current_location=0x00000000;
+	ret->label_ll=NULL;
+	return ret;
+}
+
 void free_assembler_context(struct assembler_context_t *tofree){
+	struct label_ll_t *tofree_ll=tofree->label_ll;
+	while(tofree_ll){
+		struct label_ll_t *temp=tofree_ll;
+		tofree_ll=tofree_ll->next;
+		free(temp->name);
+		free(temp);
+	}
 	free(tofree);
 }

assembly.h

@@ -9,8 +9,12 @@ struct label_ll_t{
 };
 
 struct assembler_context_t{
-	struct label_ll_t label_ll;
+	struct label_ll_t *label_ll;
+	uint32_t current_location;
 };
 
-uint32_t assemble_line(char *line, __attribute__((unused)) struct assembler_context_t *assembler_context);
-void free_assembler_context(struct assembler_context_t *tofree);
+uint32_t assemble_line(char *line, struct assembler_context_t *assembler_context);
+int assembler_context_process(char* line,struct assembler_context_t *tofree);
+
+struct assembler_context_t *malloc_assembler_context();
+void free_assembler_context(struct assembler_context_t *assembler_context);

main.c

@@ -85,7 +85,7 @@ int main(int argc, char* argd[] ){
 
 	if ( assemble != NULL ){
 		/* RUN ASSEMBLER */
-		struct assembler_context_t *assembler_context=malloc(sizeof(struct assembler_context_t));
+		struct assembler_context_t *assembler_context=malloc_assembler_context();
 
 		for (int i=0;i<ADDR_SIZE;i++)
 			simdata->RAM[i]=0;
@@ -94,6 +94,30 @@ int main(int argc, char* argd[] ){
 			char line [1000];
 			uint32_t opcode;
 			uint32_t addr=0;
+
+			//--------------- Build assembler context --------------------
+			while(fgets(line,sizeof(line),rom)!= NULL){
+
+				for(int i=0;line[i];i++)
+					if(line[i]==0x0a)
+						line[i]=0;
+
+				switch(assembler_context_process(line,assembler_context)){
+					case 0: break;
+					default:
+						printf("Error in getting assembler context at %s:%d\n", infile,linec+1);
+						fclose(rom);
+						free_assembler_context(assembler_context);
+						free_simdata(simdata);
+						return 1;
+				}
+				linec++;
+			}
+
+			fseek(rom, 0, SEEK_SET);
+			linec=0;
+
+			//---------------------- Assembler ---------------------------
 			while(fgets(line,sizeof(line),rom)!= NULL){
 
 				for(int i=0;line[i];i++)
@@ -102,12 +126,17 @@ int main(int argc, char* argd[] ){
 
 				opcode=assemble_line(line,assembler_context);
 
-				if(opcode>0xFFFFFFF1){
+				if(opcode>=0xFFFFFFF1){
+					if(opcode==0xFFFFFFFE)
+						printf("Error label not found %s:%d\n", infile,linec+1);
+					else
 						printf("Error assembling %s:%d\n", infile,linec+1);
 					fclose(rom);
 					free_assembler_context(assembler_context);
 					free_simdata(simdata);
 					return 1;
+				}else if(opcode==0xFFFFFFF0){
+					;/*it was empty, comment or label*/
 				}else{
 					simdata->RAM[addr]=(0xFF000000&opcode)>>24;
 					addr++;

test.asm

@@ -3,9 +3,12 @@ MOV $0x0001,%R0l
 MOV $0x0000,%R0h
 MOV $0x0000,%R1l
 MOV $0x0000,%R1h
-CALL $0x0024
-CALL $0x0024
-CALL $0x0024
-HALT
+CALL $SUBROUTINE
+CALL $SUBROUTINE
+CALL $SUBROUTINE
+JMP $END
+:SUBROUTINE
 ADD %R0,%R1
 RET
+:END
+HALT