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circuitpython/py/asmx86.c

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/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2014 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdint.h>
#include <stdio.h>
#include <assert.h>
#include <string.h>
#include "mpconfig.h"
#include "misc.h"
// wrapper around everything in this file
#if MICROPY_EMIT_X86
#include "asmx86.h"
/* all offsets are measured in multiples of 4 bytes */
#define WORD_SIZE (4)
#define OPCODE_NOP (0x90)
#define OPCODE_PUSH_R32 (0x50)
//#define OPCODE_PUSH_I32 (0x68)
//#define OPCODE_PUSH_M32 (0xff) /* /6 */
#define OPCODE_POP_R32 (0x58)
#define OPCODE_RET (0xc3)
//#define OPCODE_MOV_I8_TO_R8 (0xb0) /* +rb */
#define OPCODE_MOV_I32_TO_R32 (0xb8)
//#define OPCODE_MOV_I32_TO_RM32 (0xc7)
#define OPCODE_MOV_R32_TO_RM32 (0x89)
#define OPCODE_MOV_RM32_TO_R32 (0x8b)
#define OPCODE_LEA_MEM_TO_R32 (0x8d) /* /r */
#define OPCODE_XOR_R32_TO_RM32 (0x31) /* /r */
#define OPCODE_ADD_R32_TO_RM32 (0x01)
#define OPCODE_ADD_I32_TO_RM32 (0x81) /* /0 */
#define OPCODE_ADD_I8_TO_RM32 (0x83) /* /0 */
//#define OPCODE_SUB_R32_FROM_RM32 (0x29)
#define OPCODE_SUB_I32_FROM_RM32 (0x81) /* /5 */
#define OPCODE_SUB_I8_FROM_RM32 (0x83) /* /5 */
//#define OPCODE_SHL_RM32_BY_I8 (0xc1) /* /4 */
//#define OPCODE_SHR_RM32_BY_I8 (0xc1) /* /5 */
//#define OPCODE_SAR_RM32_BY_I8 (0xc1) /* /7 */
//#define OPCODE_CMP_I32_WITH_RM32 (0x81) /* /7 */
//#define OPCODE_CMP_I8_WITH_RM32 (0x83) /* /7 */
#define OPCODE_CMP_R32_WITH_RM32 (0x39)
//#define OPCODE_CMP_RM32_WITH_R32 (0x3b)
#define OPCODE_TEST_R8_WITH_RM8 (0x84) /* /r */
#define OPCODE_JMP_REL8 (0xeb)
#define OPCODE_JMP_REL32 (0xe9)
#define OPCODE_JCC_REL8 (0x70) /* | jcc type */
#define OPCODE_JCC_REL32_A (0x0f)
#define OPCODE_JCC_REL32_B (0x80) /* | jcc type */
#define OPCODE_SETCC_RM8_A (0x0f)
#define OPCODE_SETCC_RM8_B (0x90) /* | jcc type, /0 */
#define OPCODE_CALL_REL32 (0xe8)
#define OPCODE_CALL_RM32 (0xff) /* /2 */
#define OPCODE_LEAVE (0xc9)
#define MODRM_R32(x) ((x) << 3)
#define MODRM_RM_DISP0 (0x00)
#define MODRM_RM_DISP8 (0x40)
#define MODRM_RM_DISP32 (0x80)
#define MODRM_RM_REG (0xc0)
#define MODRM_RM_R32(x) (x)
#define IMM32_L0(x) ((x) & 0xff)
#define IMM32_L1(x) (((x) >> 8) & 0xff)
#define IMM32_L2(x) (((x) >> 16) & 0xff)
#define IMM32_L3(x) (((x) >> 24) & 0xff)
#define SIGNED_FIT8(x) (((x) & 0xffffff80) == 0) || (((x) & 0xffffff80) == 0xffffff80)
struct _asm_x86_t {
uint pass;
mp_uint_t code_offset;
mp_uint_t code_size;
byte *code_base;
byte dummy_data[8];
uint max_num_labels;
int *label_offsets;
int num_locals;
};
asm_x86_t *asm_x86_new(mp_uint_t max_num_labels) {
asm_x86_t *as;
as = m_new0(asm_x86_t, 1);
as->max_num_labels = max_num_labels;
as->label_offsets = m_new(int, max_num_labels);
return as;
}
void asm_x86_free(asm_x86_t *as, bool free_code) {
if (free_code) {
MP_PLAT_FREE_EXEC(as->code_base, as->code_size);
}
m_del_obj(asm_x86_t, as);
}
void asm_x86_start_pass(asm_x86_t *as, mp_uint_t pass) {
as->pass = pass;
as->code_offset = 0;
if (pass == ASM_X86_PASS_COMPUTE) {
// reset all labels
memset(as->label_offsets, -1, as->max_num_labels * sizeof(int));
}
}
void asm_x86_end_pass(asm_x86_t *as) {
if (as->pass == ASM_X86_PASS_COMPUTE) {
MP_PLAT_ALLOC_EXEC(as->code_offset, (void**) &as->code_base, &as->code_size);
if(as->code_base == NULL) {
assert(0);
}
}
}
// all functions must go through this one to emit bytes
STATIC byte *asm_x86_get_cur_to_write_bytes(asm_x86_t *as, int num_bytes_to_write) {
//printf("emit %d\n", num_bytes_to_write);
if (as->pass < ASM_X86_PASS_EMIT) {
as->code_offset += num_bytes_to_write;
return as->dummy_data;
} else {
assert(as->code_offset + num_bytes_to_write <= as->code_size);
byte *c = as->code_base + as->code_offset;
as->code_offset += num_bytes_to_write;
return c;
}
}
mp_uint_t asm_x86_get_code_size(asm_x86_t *as) {
return as->code_size;
}
void *asm_x86_get_code(asm_x86_t *as) {
return as->code_base;
}
STATIC void asm_x86_write_byte_1(asm_x86_t *as, byte b1) {
byte* c = asm_x86_get_cur_to_write_bytes(as, 1);
c[0] = b1;
}
STATIC void asm_x86_write_byte_2(asm_x86_t *as, byte b1, byte b2) {
byte* c = asm_x86_get_cur_to_write_bytes(as, 2);
c[0] = b1;
c[1] = b2;
}
STATIC void asm_x86_write_byte_3(asm_x86_t *as, byte b1, byte b2, byte b3) {
byte* c = asm_x86_get_cur_to_write_bytes(as, 3);
c[0] = b1;
c[1] = b2;
c[2] = b3;
}
STATIC void asm_x86_write_word32(asm_x86_t *as, int w32) {
byte* c = asm_x86_get_cur_to_write_bytes(as, 4);
c[0] = IMM32_L0(w32);
c[1] = IMM32_L1(w32);
c[2] = IMM32_L2(w32);
c[3] = IMM32_L3(w32);
}
STATIC void asm_x86_write_r32_disp(asm_x86_t *as, int r32, int disp_r32, int disp_offset) {
assert(disp_r32 != REG_ESP);
if (disp_offset == 0 && disp_r32 != REG_EBP) {
asm_x86_write_byte_1(as, MODRM_R32(r32) | MODRM_RM_DISP0 | MODRM_RM_R32(disp_r32));
} else if (SIGNED_FIT8(disp_offset)) {
asm_x86_write_byte_2(as, MODRM_R32(r32) | MODRM_RM_DISP8 | MODRM_RM_R32(disp_r32), IMM32_L0(disp_offset));
} else {
asm_x86_write_byte_1(as, MODRM_R32(r32) | MODRM_RM_DISP32 | MODRM_RM_R32(disp_r32));
asm_x86_write_word32(as, disp_offset);
}
}
STATIC void asm_x86_nop(asm_x86_t *as) {
asm_x86_write_byte_1(as, OPCODE_NOP);
}
STATIC void asm_x86_push_r32(asm_x86_t *as, int src_r32) {
asm_x86_write_byte_1(as, OPCODE_PUSH_R32 | src_r32);
}
#if 0
void asm_x86_push_i32(asm_x86_t *as, int src_i32) {
asm_x86_write_byte_1(as, OPCODE_PUSH_I32);
asm_x86_write_word32(as, src_i32);
}
void asm_x86_push_disp(asm_x86_t *as, int src_r32, int src_offset) {
asm_x86_write_byte_1(as, OPCODE_PUSH_M32);
asm_x86_write_r32_disp(as, 6, src_r32, src_offset);
}
#endif
STATIC void asm_x86_pop_r32(asm_x86_t *as, int dest_r32) {
asm_x86_write_byte_1(as, OPCODE_POP_R32 | dest_r32);
}
STATIC void asm_x86_ret(asm_x86_t *as) {
asm_x86_write_byte_1(as, OPCODE_RET);
}
void asm_x86_mov_r32_to_r32(asm_x86_t *as, int src_r32, int dest_r32) {
asm_x86_write_byte_2(as, OPCODE_MOV_R32_TO_RM32, MODRM_R32(src_r32) | MODRM_RM_REG | MODRM_RM_R32(dest_r32));
}
STATIC void asm_x86_mov_r32_to_disp(asm_x86_t *as, int src_r32, int dest_r32, int dest_disp) {
asm_x86_write_byte_1(as, OPCODE_MOV_R32_TO_RM32);
asm_x86_write_r32_disp(as, src_r32, dest_r32, dest_disp);
}
STATIC void asm_x86_mov_disp_to_r32(asm_x86_t *as, int src_r32, int src_disp, int dest_r32) {
asm_x86_write_byte_1(as, OPCODE_MOV_RM32_TO_R32);
asm_x86_write_r32_disp(as, dest_r32, src_r32, src_disp);
}
STATIC void asm_x86_lea_disp_to_r32(asm_x86_t *as, int src_r32, int src_disp, int dest_r32) {
asm_x86_write_byte_1(as, OPCODE_LEA_MEM_TO_R32);
asm_x86_write_r32_disp(as, dest_r32, src_r32, src_disp);
}
#if 0
void asm_x86_mov_i8_to_r8(asm_x86_t *as, int src_i8, int dest_r32) {
asm_x86_write_byte_2(as, OPCODE_MOV_I8_TO_R8 | dest_r32, src_i8);
}
#endif
void asm_x86_mov_i32_to_r32(asm_x86_t *as, int src_i32, int dest_r32) {
asm_x86_write_byte_1(as, OPCODE_MOV_I32_TO_R32 | dest_r32);
asm_x86_write_word32(as, src_i32);
}
// src_i32 is stored as a full word in the code, and aligned to machine-word boundary
void asm_x86_mov_i32_to_r32_aligned(asm_x86_t *as, int32_t src_i32, int dest_r32) {
// mov instruction uses 1 byte for the instruction, before the i32
while (((as->code_offset + 1) & (WORD_SIZE - 1)) != 0) {
asm_x86_nop(as);
}
asm_x86_mov_i32_to_r32(as, src_i32, dest_r32);
}
void asm_x86_xor_r32_to_r32(asm_x86_t *as, int src_r32, int dest_r32) {
asm_x86_write_byte_2(as, OPCODE_XOR_R32_TO_RM32, MODRM_R32(src_r32) | MODRM_RM_REG | MODRM_RM_R32(dest_r32));
}
void asm_x86_add_r32_to_r32(asm_x86_t *as, int src_r32, int dest_r32) {
asm_x86_write_byte_2(as, OPCODE_ADD_R32_TO_RM32, MODRM_R32(src_r32) | MODRM_RM_REG | MODRM_RM_R32(dest_r32));
}
void asm_x86_add_i32_to_r32(asm_x86_t *as, int src_i32, int dest_r32) {
if (SIGNED_FIT8(src_i32)) {
asm_x86_write_byte_2(as, OPCODE_ADD_I8_TO_RM32, MODRM_R32(0) | MODRM_RM_REG | MODRM_RM_R32(dest_r32));
asm_x86_write_byte_1(as, src_i32 & 0xff);
} else {
asm_x86_write_byte_2(as, OPCODE_ADD_I32_TO_RM32, MODRM_R32(0) | MODRM_RM_REG | MODRM_RM_R32(dest_r32));
asm_x86_write_word32(as, src_i32);
}
}
#if 0
void asm_x86_sub_r32_from_r32(asm_x86_t *as, int src_r32, int dest_r32) {
asm_x86_write_byte_2(as, OPCODE_SUB_R32_FROM_RM32, MODRM_R32(src_r32) | MODRM_RM_REG | MODRM_RM_R32(dest_r32));
}
#endif
void asm_x86_sub_i32_from_r32(asm_x86_t *as, int src_i32, int dest_r32) {
if (SIGNED_FIT8(src_i32)) {
// defaults to 32 bit operation
asm_x86_write_byte_2(as, OPCODE_SUB_I8_FROM_RM32, MODRM_R32(5) | MODRM_RM_REG | MODRM_RM_R32(dest_r32));
asm_x86_write_byte_1(as, src_i32 & 0xff);
} else {
// defaults to 32 bit operation
asm_x86_write_byte_2(as, OPCODE_SUB_I32_FROM_RM32, MODRM_R32(5) | MODRM_RM_REG | MODRM_RM_R32(dest_r32));
asm_x86_write_word32(as, src_i32);
}
}
#if 0
/* shifts not tested */
void asm_x86_shl_r32_by_imm(asm_x86_t *as, int r32, int imm) {
asm_x86_write_byte_2(as, OPCODE_SHL_RM32_BY_I8, MODRM_R32(4) | MODRM_RM_REG | MODRM_RM_R32(r32));
asm_x86_write_byte_1(as, imm);
}
void asm_x86_shr_r32_by_imm(asm_x86_t *as, int r32, int imm) {
asm_x86_write_byte_2(as, OPCODE_SHR_RM32_BY_I8, MODRM_R32(5) | MODRM_RM_REG | MODRM_RM_R32(r32));
asm_x86_write_byte_1(as, imm);
}
void asm_x86_sar_r32_by_imm(asm_x86_t *as, int r32, int imm) {
asm_x86_write_byte_2(as, OPCODE_SAR_RM32_BY_I8, MODRM_R32(7) | MODRM_RM_REG | MODRM_RM_R32(r32));
asm_x86_write_byte_1(as, imm);
}
#endif
void asm_x86_cmp_r32_with_r32(asm_x86_t *as, int src_r32_a, int src_r32_b) {
asm_x86_write_byte_2(as, OPCODE_CMP_R32_WITH_RM32, MODRM_R32(src_r32_a) | MODRM_RM_REG | MODRM_RM_R32(src_r32_b));
}
#if 0
void asm_x86_cmp_i32_with_r32(asm_x86_t *as, int src_i32, int src_r32) {
if (SIGNED_FIT8(src_i32)) {
asm_x86_write_byte_2(as, OPCODE_CMP_I8_WITH_RM32, MODRM_R32(7) | MODRM_RM_REG | MODRM_RM_R32(src_r32));
asm_x86_write_byte_1(as, src_i32 & 0xff);
} else {
asm_x86_write_byte_2(as, OPCODE_CMP_I32_WITH_RM32, MODRM_R32(7) | MODRM_RM_REG | MODRM_RM_R32(src_r32));
asm_x86_write_word32(as, src_i32);
}
}
#endif
void asm_x86_test_r8_with_r8(asm_x86_t *as, int src_r32_a, int src_r32_b) {
// TODO implement for other registers
assert(src_r32_a == REG_EAX);
assert(src_r32_b == REG_EAX);
asm_x86_write_byte_2(as, OPCODE_TEST_R8_WITH_RM8, MODRM_R32(src_r32_a) | MODRM_RM_REG | MODRM_RM_R32(src_r32_b));
}
void asm_x86_setcc_r8(asm_x86_t *as, mp_uint_t jcc_type, int dest_r8) {
asm_x86_write_byte_3(as, OPCODE_SETCC_RM8_A, OPCODE_SETCC_RM8_B | jcc_type, MODRM_R32(0) | MODRM_RM_REG | MODRM_RM_R32(dest_r8));
}
void asm_x86_label_assign(asm_x86_t *as, mp_uint_t label) {
assert(label < as->max_num_labels);
if (as->pass < ASM_X86_PASS_EMIT) {
// assign label offset
assert(as->label_offsets[label] == -1);
as->label_offsets[label] = as->code_offset;
} else {
// ensure label offset has not changed from PASS_COMPUTE to PASS_EMIT
//printf("l%d: (at %d=%ld)\n", label, as->label_offsets[label], as->code_offset);
assert(as->label_offsets[label] == as->code_offset);
}
}
STATIC int get_label_dest(asm_x86_t *as, int label) {
assert(label < as->max_num_labels);
return as->label_offsets[label];
}
void asm_x86_jmp_label(asm_x86_t *as, mp_uint_t label) {
int dest = get_label_dest(as, label);
int rel = dest - as->code_offset;
if (dest >= 0 && rel < 0) {
// is a backwards jump, so we know the size of the jump on the first pass
// calculate rel assuming 8 bit relative jump
rel -= 2;
if (SIGNED_FIT8(rel)) {
asm_x86_write_byte_2(as, OPCODE_JMP_REL8, rel & 0xff);
} else {
rel += 2;
goto large_jump;
}
} else {
// is a forwards jump, so need to assume it's large
large_jump:
rel -= 5;
asm_x86_write_byte_1(as, OPCODE_JMP_REL32);
asm_x86_write_word32(as, rel);
}
}
void asm_x86_jcc_label(asm_x86_t *as, mp_uint_t jcc_type, mp_uint_t label) {
int dest = get_label_dest(as, label);
int rel = dest - as->code_offset;
if (dest >= 0 && rel < 0) {
// is a backwards jump, so we know the size of the jump on the first pass
// calculate rel assuming 8 bit relative jump
rel -= 2;
if (SIGNED_FIT8(rel)) {
asm_x86_write_byte_2(as, OPCODE_JCC_REL8 | jcc_type, rel & 0xff);
} else {
rel += 2;
goto large_jump;
}
} else {
// is a forwards jump, so need to assume it's large
large_jump:
rel -= 6;
asm_x86_write_byte_2(as, OPCODE_JCC_REL32_A, OPCODE_JCC_REL32_B | jcc_type);
asm_x86_write_word32(as, rel);
}
}
void asm_x86_entry(asm_x86_t *as, mp_uint_t num_locals) {
asm_x86_push_r32(as, REG_EBP);
asm_x86_mov_r32_to_r32(as, REG_ESP, REG_EBP);
if (num_locals > 0) {
asm_x86_sub_i32_from_r32(as, num_locals * WORD_SIZE, REG_ESP);
}
asm_x86_push_r32(as, REG_EBX);
asm_x86_push_r32(as, REG_ESI);
asm_x86_push_r32(as, REG_EDI);
// TODO align stack on 16-byte boundary
as->num_locals = num_locals;
}
void asm_x86_exit(asm_x86_t *as) {
asm_x86_pop_r32(as, REG_EDI);
asm_x86_pop_r32(as, REG_ESI);
asm_x86_pop_r32(as, REG_EBX);
asm_x86_write_byte_1(as, OPCODE_LEAVE);
asm_x86_ret(as);
}
#if 0
void asm_x86_push_arg(asm_x86_t *as, int src_arg_num) {
asm_x86_push_disp(as, REG_EBP, 2 * WORD_SIZE + src_arg_num * WORD_SIZE);
}
#endif
void asm_x86_mov_arg_to_r32(asm_x86_t *as, int src_arg_num, int dest_r32) {
asm_x86_mov_disp_to_r32(as, REG_EBP, 2 * WORD_SIZE + src_arg_num * WORD_SIZE, dest_r32);
}
#if 0
void asm_x86_mov_r32_to_arg(asm_x86_t *as, int src_r32, int dest_arg_num) {
asm_x86_mov_r32_to_disp(as, src_r32, REG_EBP, 2 * WORD_SIZE + dest_arg_num * WORD_SIZE);
}
#endif
// locals:
// - stored on the stack in ascending order
// - numbered 0 through as->num_locals-1
// - EBP points above the last local
//
// | EPB
// v
// l0 l1 l2 ... l(n-1)
// ^ ^
// | low address | high address in RAM
//
STATIC int asm_x86_local_offset_from_ebp(asm_x86_t *as, int local_num) {
return (-as->num_locals + local_num) * WORD_SIZE;
}
void asm_x86_mov_local_to_r32(asm_x86_t *as, int src_local_num, int dest_r32) {
asm_x86_mov_disp_to_r32(as, REG_EBP, asm_x86_local_offset_from_ebp(as, src_local_num), dest_r32);
}
void asm_x86_mov_r32_to_local(asm_x86_t *as, int src_r32, int dest_local_num) {
asm_x86_mov_r32_to_disp(as, src_r32, REG_EBP, asm_x86_local_offset_from_ebp(as, dest_local_num));
}
void asm_x86_mov_local_addr_to_r32(asm_x86_t *as, int local_num, int dest_r32) {
int offset = asm_x86_local_offset_from_ebp(as, local_num);
if (offset == 0) {
asm_x86_mov_r32_to_r32(as, REG_EBP, dest_r32);
} else {
asm_x86_lea_disp_to_r32(as, REG_EBP, offset, dest_r32);
}
}
#if 0
void asm_x86_push_local(asm_x86_t *as, int local_num) {
asm_x86_push_disp(as, REG_EBP, asm_x86_local_offset_from_ebp(as, local_num));
}
void asm_x86_push_local_addr(asm_x86_t *as, int local_num, int temp_r32)
{
asm_x86_mov_r32_to_r32(as, REG_EBP, temp_r32);
asm_x86_add_i32_to_r32(as, asm_x86_local_offset_from_ebp(as, local_num), temp_r32);
asm_x86_push_r32(as, temp_r32);
}
#endif
void asm_x86_call_ind(asm_x86_t *as, void *ptr, mp_uint_t n_args, int temp_r32) {
// TODO align stack on 16-byte boundary before the call
assert(n_args <= 3);
if (n_args > 2) {
asm_x86_push_r32(as, REG_ARG_3);
}
if (n_args > 1) {
asm_x86_push_r32(as, REG_ARG_2);
}
if (n_args > 0) {
asm_x86_push_r32(as, REG_ARG_1);
}
#ifdef __LP64__
// We wouldn't run x86 code on an x64 machine. This is here to enable
// testing of the x86 emitter only.
asm_x86_mov_i32_to_r32(as, (int32_t)(int64_t)ptr, temp_r32);
#else
// If we get here, sizeof(int) == sizeof(void*).
asm_x86_mov_i32_to_r32(as, (int32_t)ptr, temp_r32);
#endif
asm_x86_write_byte_2(as, OPCODE_CALL_RM32, MODRM_R32(2) | MODRM_RM_REG | MODRM_RM_R32(temp_r32));
// this reduces code size by 2 bytes per call, but doesn't seem to speed it up at all
/*
asm_x86_write_byte_1(as, OPCODE_CALL_REL32);
asm_x86_write_word32(as, ptr - (void*)(as->code_base + as->code_offset + 4));
*/
// the caller must clean up the stack
if (n_args > 0) {
asm_x86_add_i32_to_r32(as, WORD_SIZE * n_args, REG_ESP);
}
}
#endif // MICROPY_EMIT_X86
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