eaxhla/source/assembler.c
2024-07-04 10:18:04 -04:00

138 lines
4.6 KiB
C

#include "assembler.h"
#include <stdlib.h>
/*
gcc -c -ansi -Wall -Wextra -Wpedantic -Werror:
-- warns about trailing comma in enumerations.
-- kept because of chad coding standard.
-- unused functions for now, obviously...
clang -c -ansi -Weverything -Werror:
-- exactly same warnings as with gcc above.
splint -fcnuse +boolint +charint assembler.c:
-- we obviously ignore unused functions for now.
-- we assume bool is int, which is true.
-- we assume char is int, which is true.
-- assembler.c:167:13: Function fabs shadows outer declaration
-- ^ function from <math.h>, which we don't even use.
splint assembler.h:
-- no warnings at all.
*/
#define REGULAR_START (ADD)
#define REGULAR_COUNT (UMUL - REGULAR_START)
#define IRREGULAR_START (UMUL)
#define IRREGULAR_COUNT (NOP - IRREGULAR_START)
#define SPECIAL_1_START (NOP)
#define SPECIAL_1_COUNT (SYSENTER - SPECIAL_1_START)
#define SPECIAL_2_START (SYSENTER)
#define SPECIAL_2_COUNT (ENTER - SPECIAL_2_START)
typedef signed int form;
typedef unsigned int next;
typedef unsigned char byte;
static next input_count; /* SHOULD I EXPOSE THESE? */
static form * input_array;
static next output_count;
static byte * output_array;
static void place (form when, byte data) {
output_array [output_count] = data;
output_count += (next) when;
}
static form valid (form data) { return ((data >= 0) && (data <= 15)); }
static form lower (form data) { return ((data >= 0) && (data <= 7)); }
static form upper (form data) { return ((data >= 8) && (data <= 15)); }
static void build_short_prefix (form when) {
place (when, 0X66);
}
static void build_long_prefix (form when,
size_index size,
type_index to,
form destination,
type_index from,
form source) {
place (when, (byte) (0X40
+ 0X01 * ((to == REG) && (upper (destination)))
+ 0X04 * ((from == REG) && (upper (source)))
+ 0X08 * (size == D64)));
}
static void build_register_direction (form when,
form destination,
form source) { /* LENGTH */
place (when, (byte) (0XC0 + 0X01 * (destination % 8) + 0X08 * (source % 8)));
}
static void build_register_redirection (form when,
form direction) {
place (when, (byte) (0X05 + 0X08 * (direction % 8)));
}
static void build_constant (form when,
size_index size) {
place (when, (byte) (0X80 + 0X01 * (size != D8)));
}
static void build_regular_instruction (form when,
byte code,
size_index size,
type_index to,
form destination,
type_index from) {
place (when, (byte) (code
+ destination % 8 * ((to == REG) && (from == IMM))
+ 0X01 * (size != D8)
+ 0X02 * ((from == MEM) && (to == REG))
+ 0X04 * ((from == IMM) && (to == MEM))
+ 0XC0 * ((from == IMM) && (to == REG))));
}
static void build_regular (operation_index operation,
size_index size,
type_index to,
form destination,
type_index from,
form source) {
build_short_prefix (size == D16);
build_long_prefix ((size == D64)
|| ((to == REG) && (upper (destination)))
|| ((from == REG) && (upper (source))),
size, to, destination, from, source);
build_constant (from == IMM, size);
build_regular_instruction (1, (byte) (0X08 * operation),
size, to, destination, from);
build_register_direction ((to == REG) && (from == REG),
destination, source);
build_register_redirection ((to == REG) && (from == MEM), destination);
build_register_redirection ((to == MEM) && (from == REG), source);
}
static void build_special_1 (operation_index operation) {
const byte data [1 * SPECIAL_1_COUNT] = {
0X90, 0XC3, 0XCB, 0XC9, 0XF0, 0XF4
};
place (1, data [operation - SPECIAL_1_START]);
}
static void build_special_2 (operation_index operation) {
const byte data [2 * SPECIAL_2_COUNT] = {
0X0F, 0X0F, 0X0F, 0X0F, 0XF3, 0X0F,
0X34, 0X35, 0X05, 0X07, 0X90, 0XA2
};
place (1, data [operation - SPECIAL_2_START]);
place (1, data [operation - SPECIAL_2_START + SPECIAL_2_COUNT]);
}