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py/asmxtensa: Add low-level Xtensa assembler.
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‎py/asmxtensa.c‎

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/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2016 Damien P. George
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <stdio.h>
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#include <assert.h>
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#include "py/mpconfig.h"
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// wrapper around everything in this file
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#if MICROPY_EMIT_XTENSA
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#include "py/asmxtensa.h"
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#define WORD_SIZE (4)
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#define SIGNED_FIT8(x) ((((x) & 0xffffff80) == 0) || (((x) & 0xffffff80) == 0xffffff80))
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#define SIGNED_FIT12(x) ((((x) & 0xfffff800) == 0) || (((x) & 0xfffff800) == 0xfffff800))
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void asm_xtensa_end_pass(asm_xtensa_t *as) {
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as->num_const = as->cur_const;
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as->cur_const = 0;
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#if 0
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// make a hex dump of the machine code
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if (as->base.pass == MP_ASM_PASS_EMIT) {
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uint8_t *d = as->base.code_base;
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printf("XTENSA ASM:");
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for (int i = 0; i < ((as->base.code_size + 15) & ~15); ++i) {
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if (i % 16 == 0) {
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printf("\n%08x:", (uint32_t)&d[i]);
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}
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if (i % 2 == 0) {
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printf(" ");
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}
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printf("%02x", d[i]);
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}
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printf("\n");
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}
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#endif
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}
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void asm_xtensa_entry(asm_xtensa_t *as, int num_locals) {
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// jump over the constants
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asm_xtensa_op_j(as, as->num_const * WORD_SIZE + 4 - 4);
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mp_asm_base_get_cur_to_write_bytes(&as->base, 1); // padding/alignment byte
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as->const_table = (uint32_t*)mp_asm_base_get_cur_to_write_bytes(&as->base, as->num_const * 4);
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// adjust the stack-pointer to store a0, a12, a13, a14 and locals, 16-byte aligned
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as->stack_adjust = (((4 + num_locals) * WORD_SIZE) + 15) & ~15;
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asm_xtensa_op_addi(as, ASM_XTENSA_REG_A1, ASM_XTENSA_REG_A1, -as->stack_adjust);
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// save return value (a0) and callee-save registers (a12, a13, a14)
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asm_xtensa_op_s32i_n(as, ASM_XTENSA_REG_A0, ASM_XTENSA_REG_A1, 0);
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asm_xtensa_op_s32i_n(as, ASM_XTENSA_REG_A12, ASM_XTENSA_REG_A1, 1);
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asm_xtensa_op_s32i_n(as, ASM_XTENSA_REG_A13, ASM_XTENSA_REG_A1, 2);
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asm_xtensa_op_s32i_n(as, ASM_XTENSA_REG_A14, ASM_XTENSA_REG_A1, 3);
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}
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void asm_xtensa_exit(asm_xtensa_t *as) {
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// restore registers
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asm_xtensa_op_l32i_n(as, ASM_XTENSA_REG_A14, ASM_XTENSA_REG_A1, 3);
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asm_xtensa_op_l32i_n(as, ASM_XTENSA_REG_A13, ASM_XTENSA_REG_A1, 2);
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asm_xtensa_op_l32i_n(as, ASM_XTENSA_REG_A12, ASM_XTENSA_REG_A1, 1);
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asm_xtensa_op_l32i_n(as, ASM_XTENSA_REG_A0, ASM_XTENSA_REG_A1, 0);
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// restore stack-pointer and return
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asm_xtensa_op_addi(as, ASM_XTENSA_REG_A1, ASM_XTENSA_REG_A1, as->stack_adjust);
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asm_xtensa_op_ret_n(as);
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}
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STATIC uint32_t get_label_dest(asm_xtensa_t *as, uint label) {
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assert(label < as->base.max_num_labels);
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return as->base.label_offsets[label];
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}
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void asm_xtensa_op16(asm_xtensa_t *as, uint16_t op) {
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uint8_t *c = mp_asm_base_get_cur_to_write_bytes(&as->base, 2);
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c[0] = op;
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c[1] = op >> 8;
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}
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void asm_xtensa_op24(asm_xtensa_t *as, uint32_t op) {
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uint8_t *c = mp_asm_base_get_cur_to_write_bytes(&as->base, 3);
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c[0] = op;
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c[1] = op >> 8;
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c[2] = op >> 16;
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}
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void asm_xtensa_j_label(asm_xtensa_t *as, uint label) {
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uint32_t dest = get_label_dest(as, label);
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int32_t rel = dest - as->base.code_offset - 4;
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// we assume rel, as a signed int, fits in 18-bits
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asm_xtensa_op_j(as, rel);
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}
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void asm_xtensa_bccz_reg_label(asm_xtensa_t *as, uint cond, uint reg, uint label) {
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uint32_t dest = get_label_dest(as, label);
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int32_t rel = dest - as->base.code_offset - 4;
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if (as->base.pass == MP_ASM_PASS_EMIT && !SIGNED_FIT12(rel)) {
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printf("ERROR: xtensa bccz out of range\n");
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}
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asm_xtensa_op_bccz(as, cond, reg, rel);
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}
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void asm_xtensa_bcc_reg_reg_label(asm_xtensa_t *as, uint cond, uint reg1, uint reg2, uint label) {
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uint32_t dest = get_label_dest(as, label);
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int32_t rel = dest - as->base.code_offset - 4;
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if (as->base.pass == MP_ASM_PASS_EMIT && !SIGNED_FIT8(rel)) {
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printf("ERROR: xtensa bcc out of range\n");
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}
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asm_xtensa_op_bcc(as, cond, reg1, reg2, rel);
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}
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// convenience function; reg_dest must be different from reg_src[12]
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void asm_xtensa_setcc_reg_reg_reg(asm_xtensa_t *as, uint cond, uint reg_dest, uint reg_src1, uint reg_src2) {
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asm_xtensa_op_movi_n(as, reg_dest, 1);
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asm_xtensa_op_bcc(as, cond, reg_src1, reg_src2, 1);
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asm_xtensa_op_movi_n(as, reg_dest, 0);
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}
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void asm_xtensa_mov_reg_i32(asm_xtensa_t *as, uint reg_dest, uint32_t i32) {
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if (SIGNED_FIT12(i32)) {
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asm_xtensa_op_movi(as, reg_dest, i32);
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} else {
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// load the constant
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asm_xtensa_op_l32r(as, reg_dest, as->base.code_offset, 4 + as->cur_const * WORD_SIZE);
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// store the constant in the table
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if (as->base.pass == MP_ASM_PASS_EMIT) {
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as->const_table[as->cur_const] = i32;
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}
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++as->cur_const;
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}
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}
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void asm_xtensa_mov_local_reg(asm_xtensa_t *as, int local_num, uint reg_src) {
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asm_xtensa_op_s32i(as, reg_src, ASM_XTENSA_REG_A1, 4 + local_num);
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}
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void asm_xtensa_mov_reg_local(asm_xtensa_t *as, uint reg_dest, int local_num) {
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asm_xtensa_op_l32i(as, reg_dest, ASM_XTENSA_REG_A1, 4 + local_num);
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}
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void asm_xtensa_mov_reg_local_addr(asm_xtensa_t *as, uint reg_dest, int local_num) {
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asm_xtensa_op_mov_n(as, reg_dest, ASM_XTENSA_REG_A1);
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asm_xtensa_op_addi(as, reg_dest, reg_dest, (4 + local_num) * WORD_SIZE);
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}
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#endif // MICROPY_EMIT_XTENSA

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