522 lines
15 KiB
C
522 lines
15 KiB
C
#include <stdint.h>
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#include <stdio.h>
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#include <limits.h>
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#include <string.h>
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#include <stdlib.h>
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//TODO: Pass file struct and currently read bytes via param
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enum DT_INSTRUCTIONS
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{
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MOV_RM_TF_R = 0b1000'10, //d w
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MOV_I_T_RM = 0b1100'011, // w
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MOV_I_T_R = 0b1011, // w reg
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MOV_M_T_A = 0b1010'000, // w
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MOV_A_T_M = 0b1010'001, // w
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MOV_RM_T_SR = 0b1000'1110,
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MOV_SR_T_RM = 0b1000'1100,
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};
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enum MOV_REGISTER_MODE
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{
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MEM_NO_DISP = 0b00,
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MEM_8BIT_DISP = 0b01,
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MEM_16BIT_DISP = 0b10,
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REG_NO_DISP = 0b11
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};
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#define REG_ENCODING_TXT_LEN 3
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char REG_ENCODING_TXT[0b10000][REG_ENCODING_TXT_LEN] = { "al", "cl", "dl", "bl", "ah", "ch", "dh", "bh",
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"ax", "cx", "dx", "bx", "sp", "bp", "si", "di" };
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#define EA_ENCODING_TXT_LEN 8
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char EA_ENCODING_TXT[0b1000][EA_ENCODING_TXT_LEN] = { "bx + si", "bx + di", "bp + si", "bp + di",
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"si", "di", "bp", "bx" };
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#define WORD_SIGNAL_LEN 6
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char WORD_SIGNAL_TXT[0b10][WORD_SIGNAL_LEN] = { "byte ", "word " };
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/* enum REG_ENCODING */
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/* { */
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/* R_AL = 0b000, */
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/* R_CL = 0b001, */
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/* R_DL = 0b010, */
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/* R_BL = 0b011, */
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/* R_AH = 0b100, */
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/* R_CH = 0b101, */
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/* R_DH = 0b110, */
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/* R_BH = 0b111 */
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/* }; */
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/* enum WREG_ENCODING */
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/* { */
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/* WR_AX = 0b000, */
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/* WR_CX = 0b001, */
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/* WR_DX = 0b010, */
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/* WR_BX = 0b011, */
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/* WR_SP = 0b100, */
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/* WR_BP = 0b101, */
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/* WR_SI = 0b110, */
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/* WR_DI = 0b111 */
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/* }; */
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typedef struct
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{
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FILE *binary;
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uint64_t size;
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} binary_data;
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FILE *output;
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binary_data bin;
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int MOV_MA_T_AM_parse(uint8_t byte1, uint8_t byte2, binary_data *binary, int bytes_read, bool is_M_T_A)
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{
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const uint8_t wide_mask = 0b0000'0001;
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uint8_t extra_bytes_read;
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unsigned char byte[1];
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uint8_t acc_wide = 0;
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uint8_t high_addr = 0;
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uint16_t word_addr = byte2;
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int disp_len = 0;
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char ea_string[18] = {'\0'};
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char *ea_string_write_ptr = ea_string;
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//Immediate value retrieval
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if (wide_mask & byte1)
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{
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fread(byte, sizeof(byte), 1, bin.binary);
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extra_bytes_read++;
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high_addr = (uint8_t)byte[0];
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word_addr = word_addr + (high_addr << 8);
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}
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//target reg retrieval
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acc_wide = (((byte1 & wide_mask)) * 8);
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//Stringify address
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//EA STRING GENERATION
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*ea_string_write_ptr = '[';
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ea_string_write_ptr++;
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disp_len = sprintf(ea_string_write_ptr, "%d", word_addr);
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ea_string_write_ptr += disp_len;
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*ea_string_write_ptr = ']';
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//END
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printf("%s %s, %s\n", "mov", is_M_T_A ? REG_ENCODING_TXT[acc_wide] : ea_string,
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is_M_T_A ? ea_string : REG_ENCODING_TXT[acc_wide]);
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fprintf(output, "%s %s, %s\n", "mov", is_M_T_A ? REG_ENCODING_TXT[acc_wide] : ea_string,
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is_M_T_A ? ea_string : REG_ENCODING_TXT[acc_wide]);
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return extra_bytes_read;
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}
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int MOV_I_T_R_parse(uint8_t byte1, uint8_t byte2, binary_data *binary, int bytes_read)
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{
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const uint8_t wide_mask = 0b0000'1000;
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const uint8_t reg_mask = 0b0000'0111;
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unsigned char byte[1];
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uint8_t extra_bytes_read = 0;
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uint16_t full_im = byte2;
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uint8_t high_im = 0;
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uint8_t reg_value = 0;
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//Immediate value retrieval
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if (wide_mask & byte1)
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{
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fread(byte, sizeof(byte), 1, bin.binary);
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extra_bytes_read++;
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high_im = (uint8_t)byte[0];
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full_im = full_im + (high_im << 8);
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}
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//target reg retrieval
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reg_value = (byte1 & reg_mask) + (((byte1 & wide_mask) >> 3) * 8);
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printf("%s %s, %d\n", "mov", REG_ENCODING_TXT[reg_value], full_im);
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fprintf(output, "%s %s, %d\n", "mov", REG_ENCODING_TXT[reg_value], full_im);
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return extra_bytes_read;
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}
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typedef struct {
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char* string;
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uint64_t len;
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} output_string;
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void fill_ea_string(output_string *str, char* content, int16_t displacement)
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{
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//EA STRING GENERATION
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char* str_beg = str->string;
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uint64_t disp_len = 0;
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*(str->string) = '[';
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str->string++;
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str->len++;
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memcpy(str->string, content, strlen(content));
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str->string += strlen(content);
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str->len += strlen(content);
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if (displacement)
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{
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if (strlen(content) > 0)
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{
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memcpy(str->string, " + ", 3);
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str->string += 3;
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str->len += 3;
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}
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disp_len = sprintf(str->string, "%d", displacement);
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str->string += disp_len;
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str->len += disp_len;
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}
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*(str->string) = ']';
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str->string = str_beg;
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str->len += 2;
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//END
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return;
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}
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int MOV_I_T_RM_parse(uint8_t byte1, uint8_t byte2, binary_data *binary, int bytes_read)
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{
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const uint8_t wide_mask = 0b0000'0001;
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const uint8_t mod_mask = 0b1100'0000;
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const uint8_t regm_mask = 0b0000'0111;
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unsigned char byte[1];
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unsigned char payload[4];
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uint8_t high_disp = 0;
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uint16_t wide_disp = 0;
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uint8_t high_data = 0;
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uint16_t wide_data = 0;
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bool is_wide = wide_mask & byte1;
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uint8_t extra_bytes_read = 0;
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//Effective Address string compose vars
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char ea_string[18] = {'\0'};
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char *ea_string_write_ptr = ea_string;
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//Immediate value string compose vars
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output_string mem_data;
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mem_data.len = 0;
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mem_data.string = calloc(18, sizeof(char)); //"[bp + di + 65535]\0"
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//Number of chars disp value takes
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int disp_len = 0;
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enum MOV_REGISTER_MODE inst_mod = (byte2 & mod_mask) >> 6;
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uint8_t extra_bytes = 1 + is_wide;
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uint8_t reg_value = 0;
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uint8_t ea_table_value = (byte2 & regm_mask);
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switch (inst_mod)
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{
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case (REG_NO_DISP):
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printf("Oh. This happened.\n");
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//This shouldn't happen, right?
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break;
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case (MEM_NO_DISP):
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//If R/M equals 110, there actually is displacement to worry about
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bool is_direct_address = (ea_table_value == 0b110);
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if (is_direct_address)
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extra_bytes += 1 + is_wide;
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for (int i = 0; i < extra_bytes; i++)
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{
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fread(&(payload[i]), sizeof(byte), 1, bin.binary);
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extra_bytes_read++;
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}
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//Composing displacement and immediate values
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if (is_direct_address)
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{
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wide_disp = payload[0];
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if (is_wide)
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{
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wide_disp = (payload[1] << 8) + wide_disp;
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wide_data = payload[2];
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wide_data = (payload[3] << 8) + wide_data;
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}
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else
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{
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wide_data = payload[1];
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}
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}
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else
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{
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wide_data = payload[0];
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if (is_wide)
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wide_data = (payload[1] << 8) + wide_data;
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}
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fill_ea_string(&mem_data, (is_direct_address ? "" : EA_ENCODING_TXT[ea_table_value]), wide_disp);
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printf("%s %s, %s%d\n", "mov", mem_data.string, WORD_SIGNAL_TXT[is_wide], wide_data);
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fprintf(output, "%s %s, %s%d\n", "mov", mem_data.string, WORD_SIGNAL_TXT[is_wide], wide_data);
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break;
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case (MEM_8BIT_DISP):
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//If R/M equals 110, there actually is displacement to worry about
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extra_bytes += 1;
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for (int i = 0; i < extra_bytes; i++)
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{
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fread(&(payload[i]), sizeof(byte), 1, bin.binary);
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extra_bytes_read++;
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}
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//Composing displacement and immediate values
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wide_disp = payload[0];
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wide_data = payload[1];
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if (is_wide)
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{
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wide_data = (payload[2] << 8) + wide_data;
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}
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fill_ea_string(&mem_data, EA_ENCODING_TXT[ea_table_value], wide_disp);
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printf("%s %s, %s%d\n", "mov", mem_data.string, WORD_SIGNAL_TXT[is_wide], wide_data);
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fprintf(output, "%s %s, %s%d\n", "mov", mem_data.string, WORD_SIGNAL_TXT[is_wide], wide_data);
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break;
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case (MEM_16BIT_DISP):
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//If R/M equals 110, there actually is displacement to worry about
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extra_bytes += 2;
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for (int i = 0; i < extra_bytes; i++)
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{
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fread(&(payload[i]), sizeof(byte), 1, bin.binary);
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extra_bytes_read++;
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}
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//Composing displacement and immediate values
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wide_disp = payload[0];
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wide_disp = (payload[1] << 8) + wide_disp;
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wide_data = payload[2];
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if (is_wide)
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{
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wide_data = (payload[3] << 8) + wide_data;
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}
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fill_ea_string(&mem_data, EA_ENCODING_TXT[ea_table_value], wide_disp);
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printf("%s %s, %s%d\n", "mov", mem_data.string, WORD_SIGNAL_TXT[is_wide], wide_data);
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fprintf(output, "%s %s, %s%d\n", "mov", mem_data.string, WORD_SIGNAL_TXT[is_wide], wide_data);
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break;
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}
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return extra_bytes_read;
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}
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int MOV_RM_TF_R_parse(uint8_t byte1, uint8_t byte2, binary_data *binary, int bytes_read)
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{
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const uint8_t wide_mask = 0b0000'0001;
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const uint8_t dest_mask = 0b0000'0010;
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const uint8_t mod_mask = 0b1100'0000;
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const uint8_t regm_mask = 0b0011'1000;
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unsigned char byte[1];
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uint8_t low_disp = 0;
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uint8_t high_disp = 0;
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uint16_t wide_disp = 0;
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uint8_t extra_bytes_read = 0;
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bool reg_is_dest = (byte1 & dest_mask);
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uint8_t inst_mod = (byte2 & mod_mask) >> 6;
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//Effective Address string compose vars
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char ea_string[18] = {'\0'};
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char *ea_string_write_ptr = ea_string;
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//Number of chars disp value takes
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int disp_len = 0;
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uint8_t reg_value = 0;
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uint8_t ea_table_value = 0;
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switch (inst_mod)
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{
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case (REG_NO_DISP):
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//Since we're doing register mode/register to register, both reg and r/m are affected by the W bit
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//if D=1, dest is retrieved from the reg field in byte2 and src from r/m
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uint8_t dest_value = (reg_is_dest) ? ((byte2 & regm_mask) >> 3) + ((byte1 & wide_mask) * 8)
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: (byte2 & (regm_mask >> 3)) + ((byte1 & wide_mask) * 8);
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uint8_t src_value = (reg_is_dest) ? (byte2 & (regm_mask >> 3)) + ((byte1 & wide_mask) * 8)
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: ((byte2 & regm_mask) >> 3) + ((byte1 & wide_mask) * 8);
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printf("%s %s, %s\n", "mov", REG_ENCODING_TXT[dest_value], REG_ENCODING_TXT[src_value]);
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fprintf(output, "%s %s, %s\n", "mov", REG_ENCODING_TXT[dest_value], REG_ENCODING_TXT[src_value]);
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break;
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case (MEM_8BIT_DISP):
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fread(byte, sizeof(byte), 1, bin.binary);
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extra_bytes_read++;
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low_disp = (uint8_t)byte[0];
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reg_value = ((byte2 & regm_mask) >> 3) + ((byte1 & wide_mask) * 8);
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ea_table_value = (byte2 & (regm_mask >> 3));
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//EA STRING GENERATION
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*ea_string_write_ptr = '[';
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ea_string_write_ptr++;
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memcpy(ea_string_write_ptr, EA_ENCODING_TXT[ea_table_value], strlen(EA_ENCODING_TXT[ea_table_value]));
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ea_string_write_ptr += strlen(EA_ENCODING_TXT[ea_table_value]);
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memcpy(ea_string_write_ptr, " + ", 3);
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ea_string_write_ptr += 3;
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disp_len = sprintf(ea_string_write_ptr, "%d", low_disp);
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ea_string_write_ptr += disp_len;
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*ea_string_write_ptr = ']';
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//END
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printf("%s %s, %s\n", "mov", (reg_is_dest ? REG_ENCODING_TXT[reg_value]
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: ea_string)
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, (reg_is_dest ? ea_string
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: REG_ENCODING_TXT[reg_value]));
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fprintf(output, "%s %s, %s\n", "mov", (reg_is_dest ? REG_ENCODING_TXT[reg_value]
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: ea_string)
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, (reg_is_dest ? ea_string
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: REG_ENCODING_TXT[reg_value]));
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break;
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case (MEM_16BIT_DISP):
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fread(byte, sizeof(byte), 1, bin.binary);
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extra_bytes_read++;
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low_disp = (uint8_t)byte[0];
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fread(byte, sizeof(byte), 1, bin.binary);
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extra_bytes_read++;
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high_disp = (uint8_t)byte[0];
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//Composing wide displacement
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wide_disp = high_disp << 8;
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wide_disp = wide_disp | low_disp;
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reg_value = ((byte2 & regm_mask) >> 3) + ((byte1 & wide_mask) * 8);
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ea_table_value = (byte2 & (regm_mask >> 3));
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//EA STRING GENERATION
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*ea_string_write_ptr = '[';
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ea_string_write_ptr++;
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memcpy(ea_string_write_ptr, EA_ENCODING_TXT[ea_table_value], strlen(EA_ENCODING_TXT[ea_table_value]));
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ea_string_write_ptr += strlen(EA_ENCODING_TXT[ea_table_value]);
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memcpy(ea_string_write_ptr, " + ", 3);
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ea_string_write_ptr += 3;
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disp_len = sprintf(ea_string_write_ptr, "%d", wide_disp);
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ea_string_write_ptr += disp_len;
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*ea_string_write_ptr = ']';
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//END
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printf("%s %s, %s\n", "mov", (reg_is_dest ? REG_ENCODING_TXT[reg_value]
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: ea_string)
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, (reg_is_dest ? ea_string
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: REG_ENCODING_TXT[reg_value]));
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fprintf(output, "%s %s, %s\n", "mov", (reg_is_dest ? REG_ENCODING_TXT[reg_value]
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: ea_string)
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, (reg_is_dest ? ea_string
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: REG_ENCODING_TXT[reg_value]));
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break;
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case (MEM_NO_DISP):
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//Checking if special case 110 applies
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ea_table_value = (byte2 & (regm_mask >> 3));
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//If R/M equals 110, there actually is displacement to worry about
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bool is_direct_address = (ea_table_value == 0b110);
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if (is_direct_address)
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{
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fread(byte, sizeof(byte), 1, bin.binary);
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extra_bytes_read++;
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low_disp = (uint8_t)byte[0];
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fread(byte, sizeof(byte), 1, bin.binary);
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extra_bytes_read++;
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high_disp = (uint8_t)byte[0];
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//Composing wide displacement
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wide_disp = high_disp << 8;
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wide_disp = wide_disp | low_disp;
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}
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reg_value = ((byte2 & regm_mask) >> 3) + ((byte1 & wide_mask) * 8);
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if (is_direct_address)
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{
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//EA STRING GENERATION
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*ea_string_write_ptr = '[';
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ea_string_write_ptr++;
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disp_len = sprintf(ea_string_write_ptr, "%d", wide_disp);
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ea_string_write_ptr += disp_len;
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*ea_string_write_ptr = ']';
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//END
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}
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else
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{
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//EA STRING GENERATION
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*ea_string_write_ptr = '[';
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ea_string_write_ptr++;
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memcpy(ea_string_write_ptr, EA_ENCODING_TXT[ea_table_value], strlen(EA_ENCODING_TXT[ea_table_value]));
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ea_string_write_ptr += strlen(EA_ENCODING_TXT[ea_table_value]);
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*ea_string_write_ptr = ']';
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//END
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}
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printf("%s %s, %s\n", "mov", (reg_is_dest ? REG_ENCODING_TXT[reg_value]
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: ea_string)
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, (reg_is_dest ? ea_string
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: REG_ENCODING_TXT[reg_value]));
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fprintf(output, "%s %s, %s\n", "mov", (reg_is_dest ? REG_ENCODING_TXT[reg_value]
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: ea_string)
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, (reg_is_dest ? ea_string
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: REG_ENCODING_TXT[reg_value]));
|
|
break;
|
|
}
|
|
return extra_bytes_read;
|
|
}
|
|
|
|
int main(int argc, char** argv)
|
|
{
|
|
if (argc != 2) return -1;
|
|
if (CHAR_BIT != 8) return -2;
|
|
|
|
unsigned char byte[1];
|
|
bin.binary = fopen(argv[1], "rb");
|
|
fseek(bin.binary, 0, SEEK_END);
|
|
bin.size = ftell(bin.binary);
|
|
fseek(bin.binary, 0, SEEK_SET);
|
|
|
|
output = fopen("output.asm", "w");
|
|
fprintf(output, "%s\n\n", "bits 16");
|
|
|
|
for (int bytes_read = 0; bytes_read < bin.size; bytes_read++)
|
|
{
|
|
uint8_t inst_byte2 = 0;
|
|
fread(byte, sizeof(byte), 1, bin.binary);
|
|
uint8_t manip_inst = (uint8_t)byte[0];
|
|
uint8_t inst = (uint8_t)byte[0];
|
|
//We're checking for all MOV except segment registers
|
|
manip_inst = (manip_inst >> 1);
|
|
switch (manip_inst)
|
|
{
|
|
case MOV_M_T_A:
|
|
case MOV_A_T_M:
|
|
if (bytes_read >= bin.size) break;
|
|
fread(byte, sizeof(byte), 1, bin.binary);
|
|
bytes_read++;
|
|
inst_byte2 = (uint8_t)byte[0];
|
|
bytes_read += MOV_MA_T_AM_parse(inst, inst_byte2, 0, 0, (manip_inst == MOV_M_T_A));
|
|
continue;
|
|
case MOV_I_T_RM:
|
|
if (bytes_read >= bin.size) break;
|
|
fread(byte, sizeof(byte), 1, bin.binary);
|
|
bytes_read++;
|
|
inst_byte2 = (uint8_t)byte[0];
|
|
bytes_read += MOV_I_T_RM_parse(inst, inst_byte2, 0, 0);
|
|
continue;
|
|
}
|
|
manip_inst = (manip_inst >> 1);
|
|
if (manip_inst == MOV_RM_TF_R)
|
|
{
|
|
if (bytes_read >= bin.size) break;
|
|
fread(byte, sizeof(byte), 1, bin.binary);
|
|
bytes_read++;
|
|
inst_byte2 = (uint8_t)byte[0];
|
|
bytes_read += MOV_RM_TF_R_parse(inst, inst_byte2, 0, 0);
|
|
continue;
|
|
}
|
|
manip_inst = (manip_inst >> 2);
|
|
if (manip_inst == MOV_I_T_R)
|
|
{
|
|
if (bytes_read >= bin.size) break;
|
|
fread(byte, sizeof(byte), 1, bin.binary);
|
|
bytes_read++;
|
|
inst_byte2 = (uint8_t)byte[0];
|
|
bytes_read += MOV_I_T_R_parse(inst, inst_byte2, 0, 0);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|