circuitpython/py/asmbase.c

114 lines
4.0 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2016 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 <assert.h>
#include <string.h>
#include "py/obj.h"
#include "py/misc.h"
#include "py/asmbase.h"
#if MICROPY_EMIT_MACHINE_CODE
void mp_asm_base_init(mp_asm_base_t *as, size_t max_num_labels) {
as->max_num_labels = max_num_labels;
as->label_offsets = m_new(size_t, max_num_labels);
}
void mp_asm_base_deinit(mp_asm_base_t *as, bool free_code) {
if (free_code) {
MP_PLAT_FREE_EXEC(as->code_base, as->code_size);
}
m_del(size_t, as->label_offsets, as->max_num_labels);
}
void mp_asm_base_start_pass(mp_asm_base_t *as, int pass) {
if (pass < MP_ASM_PASS_EMIT) {
// Reset labels so we can detect backwards jumps (and verify unique assignment)
memset(as->label_offsets, -1, as->max_num_labels * sizeof(size_t));
} else {
// allocating executable RAM is platform specific
MP_PLAT_ALLOC_EXEC(as->code_offset, (void **)&as->code_base, &as->code_size);
assert(as->code_base != NULL);
}
as->pass = pass;
as->suppress = false;
as->code_offset = 0;
}
// all functions must go through this one to emit bytes
// if as->pass < MP_ASM_PASS_EMIT, then this function just counts the number
// of bytes needed and returns NULL, and callers should not store any data
// It also returns NULL if generated code should be suppressed at this point.
uint8_t *mp_asm_base_get_cur_to_write_bytes(void *as_in, size_t num_bytes_to_write) {
mp_asm_base_t *as = as_in;
uint8_t *c = NULL;
if (as->suppress) {
return c;
}
if (as->pass == MP_ASM_PASS_EMIT) {
assert(as->code_offset + num_bytes_to_write <= as->code_size);
c = as->code_base + as->code_offset;
}
as->code_offset += num_bytes_to_write;
return c;
}
void mp_asm_base_label_assign(mp_asm_base_t *as, size_t label) {
assert(label < as->max_num_labels);
// Assiging a label ends any dead-code region, and all following machine
// code should be emitted (until another mp_asm_base_suppress_code() call).
as->suppress = false;
if (as->pass < MP_ASM_PASS_EMIT) {
// assign label offset
assert(as->label_offsets[label] == (size_t)-1);
as->label_offsets[label] = as->code_offset;
} else {
// ensure label offset has not changed from PASS_COMPUTE to PASS_EMIT
assert(as->label_offsets[label] == as->code_offset);
}
}
// align must be a multiple of 2
void mp_asm_base_align(mp_asm_base_t *as, unsigned int align) {
as->code_offset = (as->code_offset + align - 1) & (~(align - 1));
}
// this function assumes a little endian machine
void mp_asm_base_data(mp_asm_base_t *as, unsigned int bytesize, uintptr_t val) {
uint8_t *c = mp_asm_base_get_cur_to_write_bytes(as, bytesize);
if (c != NULL) {
for (unsigned int i = 0; i < bytesize; i++) {
*c++ = val;
val >>= 8;
}
}
}
#endif // MICROPY_EMIT_MACHINE_CODE