/*
 * 在线代码托管：http://git.oschina.net/cryt/asm_to_logisim_rom
 */

#include "header.h"

char optable[OP_NUM];	//存储一个命令对应的二进制机器码 读文件symbol-op.txt后确定

int main(int argc, char *argv[])
{
	char command[COMMAND_MAX_LEN];	//存放一行命令的缓冲区
	FILE *fasm;	//打开源文件指针
	FILE *fbin;	//生成目标文件指针

	int counter = 0;	//用来控制输出按照logisim格式 8个数据一行
	int line = 0;	//记录当前处理的是源代码中的哪一行
	int label_pos = 0;	//记录当前处理的是源代码有效语句的第几行（用于将标号转换为具体的位置数字）
	int error = 0;
	int error_happen = 0;

	struct label label[LABEL_NUM];
	int label_n = 0;

	readOpFile();

	if (argc == 2)
	{
		if ((fasm = fopen(argv[1], "r")) == NULL)
		{
			fprintf(stderr, "open %s failed\n", argv[1]);
			exit(-1);
		}
	}
	else
	{
		if ((fasm = fopen("src.asm", "r")) == NULL)
		{
			fprintf(stderr, "open src.asm failed\n");
			exit(-1);
		}
	}
	
	if ((fbin = fopen("rom.txt", "w")) == NULL)
	{
		fprintf(stderr, "open %s failed\n", argv[1]);
		exit(-1);
	}
	fprintf(fbin, "v2.0 raw\n");	//logisim中rom导入数据的格式

	//生成标号和行号对应关系
	while (!feof(fasm))
	{
		fgets(command, COMMAND_MAX_LEN, fasm);
		command[strlen(command)] = '\n';

		if (createLabelTable(label, &label_n, command, label_pos) == 1)
		{
			++label_pos;
		}

	}

	//回到文件起始部分
	fseek(fasm, 0, SEEK_SET);
	//循环读取源代码 每次一行 直到文件尾
	
	counter = 0;
	while (!feof(fasm))
	{
		error = 0;
		fgets(command, COMMAND_MAX_LEN, fasm);
		if (command[strlen(command) - 1] != '\n')
		{
			command[strlen(command)] = '\n';
			command[strlen(command)+1] = '\0';
		}
		++line;
		if (asmToHex(label, label_n, command, fbin, &error) == 1)
		{
			++counter;

			if (counter == 8)
			{
				counter = 0;
				fprintf(fbin, "\n");
			}
			else
				fprintf(fbin, " ");
		}
		else
		{
			if (error)
			{
				error_happen = 1;
				printError(command, error, line);
			}
		}

	}

	fclose(fasm);
	fclose(fbin);

	if (error_happen)
	{
		printf("Press Enter to Exit\n");
		getchar();
	}
	return 0;
}

//空行返回0 有效语句返回1
int asmToHex(struct label *label, int label_n, char *command, FILE *fp, int *error)
{
	int i = 0;
	int j;
	int k;
	int len;
	char *pnum;
	long addr;
	enum symbol_type status;

	//忽略前导空白符
	while (command[i] == ' ' || command[i] == '\t')
	{
		++i;
	}

	//判断是否是空行 （包括只有注释）
	if (command[i] == '\n' || command[i] == ';')
		return 0;

	j = i;
	while (command[j] != ':' && command[j] != '\n')
		++j;
	if (command[j] == ':')
	{
		i = j+1;
		while (command[i] == ' ' || command[i] == '\t')
		{
			++i;
		}
		if (command[i] == '\n')
			return 0;
	}

	
	status = whatType(command+i, &len);
	i += len;
	++i;	//现在i指向ADD [123]的'[ 或jmp 12的'1' 或 JZ s1的's'处


	if (command[i] == '[')
		++i;

	//处理jmp 标号 这种情况
	if ((status == JMP || status == JO || status == JZ) && (command[i] < '0' || command[i] > '9'))
	{
		for (j = i; command[j] != ' ' && command[j] != '\n' && command[j] != '\t' && command[j] != ';'; ++j)
			;
		for (k = 0; k < label_n; ++k)
		{
			if (strncmp(command+i, label[k].label, j-i) == 0 && label[k].label[j-i] == '\0')
			{
				fprintf(fp, "%c%03X", optable[status], label[k].pos);
				return 1;
			}
		}
		*error = 1;
		return 0;
	}

	//把文本形式的 123H 1010B 79转换为int类型保存在addr
	strtol(command+i, &pnum, 16);
	if (*pnum == 'H' || *pnum == 'h')
		addr = strtol(command+i, &pnum, 16);
	else if (*(pnum-1) == 'b' || *(pnum-1) == 'B')
		addr = strtol(command+i, &pnum, 2);
	else
		addr = strtol(command+i, &pnum, 10);


	fprintf(fp, "%c%03X", optable[status], (unsigned int)addr);
	return 1;
}

//空行返回0 有效语句返回1
int createLabelTable(struct label *label, int *label_n, char *command, int label_pos)
{
	int i = 0;
	int j;

	//忽略前导空白符
	while (command[i] == ' ' || command[i] == '\t')
	{
		++i;
	}

	//判断是否是空行 （包括只有注释）
	if (command[i] == '\n' || command[i] == ';')
		return 0;

	j = i;
	while (command[j] != ':' && command[j] != '\n')
		++j;
	if (command[j] == ':')
	{
		label[*label_n].pos = label_pos;
		strncpy(label[*label_n].label, command + i, j-i);
		label[*label_n].label[j-i] = '\0';
		++(*label_n);
	}

	if (command[j] == '\n')
		return 1;
	++j;
	while (command[j] == ' ' || command[j] == '\t')
	{
		++j;
	}
	if (command[j] == '\n')
		return 0;
	else
		return 1;
}

void readOpFile(void)
{
	FILE *fsymbol_op;
	int i;
	char op[2];
	char *pnum;
	long num;
	char command[COMMAND_MAX_LEN];	//存放一行命令的缓冲区
	enum symbol_type status;


	if ((fsymbol_op = fopen("symbol-op.txt", "r")) == NULL)
	{
		fprintf(stderr, "open symbol-op.txt failed\n");
		exit(-1);
	}

	while (!feof(fsymbol_op))
	{
		fgets(command, COMMAND_MAX_LEN, fsymbol_op);
		command[strlen(command)] = '\n';
		i = 0;
		if (command[i] == '#')
			continue;

		status = whatType(command, &i);
		

		num = strtol(command+i, &pnum, 2);
		sprintf(op, "%1X", (unsigned int)num);
		optable[status] = *op;
	}
}

//返回伪代码类型 begin指向伪指令 len返回指令长度
enum symbol_type whatType(char *begin, int *len)
{
	enum symbol_type status;
	int i = 0;

	switch (begin[0])
	{
		case 'n':
		case 'N':
			status = NOP;
			i = 3;
			break;
		case 'l':
		case 'L':
			status = LOAD;
			i = 4;
			break;
		case 'x':
		case 'X':
			status = XOR;
			i = 3;
			break;
		case 'o':
		case 'O':
			status = OR;
			i = 2;
			break;
		case 'a':
		case 'A':
			status = ADD;
			i = 3;
			break;
		case 's':
		case 'S':
			if (begin[1] == 'u' || begin[1] == 'U')
			{
				status = SUB;
				i = 3;
				break;
			}
			else
			{
				status = STORE;
				i = 5;
				break;
			}
		case 'j':
		case 'J':
			if (begin[1] == 'm' || begin[1] == 'M')
			{
				status = JMP;
				i = 3;
				break;
			}
			else if (begin[1] == 'o' || begin[1] == 'O')
			{
				status = JO;
				i = 2;
				break;
			}
			else 
			{
				status = JZ;
				i = 2;
				break;
			}
			
		case 'e':
		case 'E':
			status = EXIT;
			i = 4;
			break;
		default:
			break;
	}

	*len = i;
	return status;
}

void printError(char *command, int error, int line)
{
	int i;
	switch (error)
	{
	case 1:
		printf("第%d行错误：不认识的标号:\n", line);
		for (i = 0; command[i] != '\n'; ++i)
			putchar(command[i]);
		printf("\n");
		break;
	default:
		break;

	}
}