1-2 challenge solved (only impl in RM_TF_R)

1-2/decoder.c

@@ -160,10 +160,20 @@ void fill_ea_string(output_string *str, char* content, int16_t displacement)
 	{
 		if (strlen(content) > 0)
 		{
-			memcpy(str->string, " + ", 3);
+			*(str->string) = ' ';
+			if(displacement >= 0)
+			{	
+				*(str->string + 1) = '+';
+				*(str->string + 2) = ' ';
 	    		str->string += 3;
 	    		str->len += 3;
 			}
+			else
+			{	
+	    		str->string += 1;
+	    		str->len += 1;
+			}
+		}
 		disp_len = sprintf(str->string, "%d", displacement);
 		str->string += disp_len;
 	    str->len += disp_len;
@@ -297,10 +307,22 @@ int MOV_I_T_RM_parse(uint8_t byte1, uint8_t byte2, binary_data *binary, int byte
 		break;
 	}
 
-
 	return extra_bytes_read;
 }
 
+int16_t calc_effective_disp(uint8_t high_order, uint8_t low_order)
+{
+	const uint8_t low_order_neg_mask = 0b1000'0000;
+    int16_t effective_disp = 0;
+
+	if (high_order == 0 & ((low_order & low_order_neg_mask) >> 7))
+		high_order = high_order | 0b1111'1111;
+	int8_t *effective_disp_high_order =(int8_t*) &(effective_disp) + 1;
+	memcpy(&(effective_disp), &low_order, 1);
+	memcpy(effective_disp_high_order, &high_order, 1);
+	return effective_disp;
+}	
+
 int MOV_RM_TF_R_parse(uint8_t byte1, uint8_t byte2, binary_data *binary, int bytes_read)
 {
 	const uint8_t wide_mask = 0b0000'0001;
@@ -312,8 +334,13 @@ int MOV_RM_TF_R_parse(uint8_t byte1, uint8_t byte2, binary_data *binary, int byt
 	uint8_t low_disp   		 = 0;
 	uint8_t high_disp  		 = 0;
 	uint16_t wide_disp 		 = 0;
+	int16_t effective_disp   = 0;
 	uint8_t extra_bytes_read = 0;
 
+	output_string mem_data;
+	mem_data.len = 0;
+	mem_data.string = calloc(18, sizeof(char)); //"[bp + di + 65535]\0"
+
 	bool reg_is_dest = (byte1 & dest_mask);
     uint8_t inst_mod = (byte2 & mod_mask) >> 6;
 
@@ -342,28 +369,22 @@ int MOV_RM_TF_R_parse(uint8_t byte1, uint8_t byte2, binary_data *binary, int byt
 		fread(byte, sizeof(byte), 1, bin.binary);
 		extra_bytes_read++;
 		low_disp = (uint8_t)byte[0];
+		
 		reg_value = ((byte2 & regm_mask) >> 3) + ((byte1 & wide_mask) * 8);
 		ea_table_value = (byte2 & (regm_mask >> 3));
+		effective_disp = calc_effective_disp(0, low_disp);
 		
 		//EA STRING GENERATION
-		*ea_string_write_ptr = '[';
+        fill_ea_string(&mem_data, EA_ENCODING_TXT[ea_table_value], effective_disp);
-		ea_string_write_ptr++;
-		memcpy(ea_string_write_ptr, EA_ENCODING_TXT[ea_table_value], strlen(EA_ENCODING_TXT[ea_table_value]));
-		ea_string_write_ptr += strlen(EA_ENCODING_TXT[ea_table_value]);
-		memcpy(ea_string_write_ptr, " + ", 3);
-		ea_string_write_ptr += 3;
-		disp_len = sprintf(ea_string_write_ptr, "%d", low_disp);
-		ea_string_write_ptr += disp_len;
-		*ea_string_write_ptr = ']';
 		//END
 		
     	printf("%s %s, %s\n", "mov", (reg_is_dest ? REG_ENCODING_TXT[reg_value] 
-									  : ea_string)
+									  : mem_data.string)
-			                       , (reg_is_dest ? ea_string 
+			                       , (reg_is_dest ? mem_data.string 
 									  : REG_ENCODING_TXT[reg_value]));
 		fprintf(output, "%s %s, %s\n", "mov", (reg_is_dest ? REG_ENCODING_TXT[reg_value] 
-											  : ea_string)
+											  : mem_data.string)
-			                    		    , (reg_is_dest ? ea_string 
+			                    		    , (reg_is_dest ? mem_data.string 
 											  : REG_ENCODING_TXT[reg_value]));
 		break;
 	case (MEM_16BIT_DISP):
@@ -375,30 +396,22 @@ int MOV_RM_TF_R_parse(uint8_t byte1, uint8_t byte2, binary_data *binary, int byt
 		high_disp = (uint8_t)byte[0];
 
 		//Composing wide displacement
-		wide_disp = high_disp << 8;
+		effective_disp = calc_effective_disp(high_disp, low_disp);
-		wide_disp = wide_disp | low_disp;
+				
 		reg_value = ((byte2 & regm_mask) >> 3) + ((byte1 & wide_mask) * 8);
 		ea_table_value = (byte2 & (regm_mask >> 3));
 
 		//EA STRING GENERATION
-		*ea_string_write_ptr = '[';
+        fill_ea_string(&mem_data, EA_ENCODING_TXT[ea_table_value], effective_disp);
-		ea_string_write_ptr++;
-		memcpy(ea_string_write_ptr, EA_ENCODING_TXT[ea_table_value], strlen(EA_ENCODING_TXT[ea_table_value]));
-		ea_string_write_ptr += strlen(EA_ENCODING_TXT[ea_table_value]);
-		memcpy(ea_string_write_ptr, " + ", 3);
-		ea_string_write_ptr += 3;
-		disp_len = sprintf(ea_string_write_ptr, "%d", wide_disp);
-		ea_string_write_ptr += disp_len;
-		*ea_string_write_ptr = ']';
 		//END
 		
     	printf("%s %s, %s\n", "mov", (reg_is_dest ? REG_ENCODING_TXT[reg_value] 
-									  : ea_string)
+									  : mem_data.string)
-			                       , (reg_is_dest ? ea_string 
+			                       , (reg_is_dest ? mem_data.string 
 									  : REG_ENCODING_TXT[reg_value]));
 		fprintf(output, "%s %s, %s\n", "mov", (reg_is_dest ? REG_ENCODING_TXT[reg_value] 
-											  : ea_string)
+											  : mem_data.string)
-			                    		    , (reg_is_dest ? ea_string 
+			                    		    , (reg_is_dest ? mem_data.string
 											  : REG_ENCODING_TXT[reg_value]));
 		break;
 	case (MEM_NO_DISP):

1-2/listing-39.asm

@@ -25,7 +25,8 @@ mov ah, [bx + si + 4]
 ; Source address calculation plus 16-bit displacement
 mov al, [bx + si + 4999]
 
-; Dest address calculation
+								; Dest address calculation
+	
 mov [bx + di], cx
 mov [bp + si], cl
 mov [bp], ch

1-2/listing-40.asm

@@ -1,6 +1,9 @@
 bits 16
 
 ; Signed displacements
+mov ax, [bx - 100]
+mov ax, [bx - 3]
+mov ax, [bx + di - 40000]	
 mov ax, [bx + di - 37]
 mov [si - 300], cx
 mov dx, [bx - 32]

1-2/output.asm

@@ -1,18 +1,16 @@
 bits 16
 
-mov si, bx
+mov ax, [bx -100]
-mov dh, al
+mov ax, [bx -3]
-mov cl, 12
+mov ax, [bx + di + 25536]
-mov ch, 244
+mov ax, [bx + di -37]
-mov cx, 12
+mov [si -300], cx
-mov cx, 65524
+mov dx, [bx -32]
-mov dx, 3948
+mov [bp + di], byte 7
-mov dx, 61588
+mov [di + 901], word 347
-mov al, [bx + si]
+mov bp, [5]
-mov bx, [bp + di]
+mov bx, [3458]
-mov dx, [bp + 0]
+mov ax, [2555]
-mov ah, [bx + si + 4]
+mov ax, [16]
-mov al, [bx + si + 4999]
+mov [2554], ax
-mov [bx + di], cx
+mov [15], ax
-mov [bp + si], cl
-mov [bp + 0], ch