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Merge pull request #6397 from jepler/extra-memset 

Some flash size optimizations related to string0.c (implementation of str/mem functions)
This commit is contained in:
Dan Halbert 2022-10-13 12:34:59 -04:00 committed by GitHub
parent 7e4b2a09eb 162fa6ef02
commit 8825e7f241
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 17 additions and 12 deletions
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17
py/gc.c
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@ -138,7 +138,6 @@ void gc_init(void *start, void *end) {
MP_STATE_MEM(gc_alloc_table_start) = (byte *)start;
#if MICROPY_ENABLE_FINALISER
size_t gc_finaliser_table_byte_len = (MP_STATE_MEM(gc_alloc_table_byte_len) * BLOCKS_PER_ATB + BLOCKS_PER_FTB - 1) / BLOCKS_PER_FTB;
MP_STATE_MEM(gc_finaliser_table_start) = MP_STATE_MEM(gc_alloc_table_start) + MP_STATE_MEM(gc_alloc_table_byte_len) + 1;
#endif
@ -147,18 +146,16 @@ void gc_init(void *start, void *end) {
MP_STATE_MEM(gc_pool_end) = end;
#if MICROPY_ENABLE_FINALISER
size_t gc_finaliser_table_byte_len = (MP_STATE_MEM(gc_alloc_table_byte_len) * BLOCKS_PER_ATB + BLOCKS_PER_FTB - 1) / BLOCKS_PER_FTB;
(void)gc_finaliser_table_byte_len; // avoid unused variable diagnostic if asserts are disabled
assert(MP_STATE_MEM(gc_pool_start) >= MP_STATE_MEM(gc_finaliser_table_start) + gc_finaliser_table_byte_len);
#endif
// Clear ATBs plus one more byte. The extra byte might be read when we read the final ATB and
// then try to count its tail. Clearing the byte ensures it is 0 and ends the chain. Without an
// FTB, it'll just clear the pool byte early.
memset(MP_STATE_MEM(gc_alloc_table_start), 0, MP_STATE_MEM(gc_alloc_table_byte_len) + 1);
#if MICROPY_ENABLE_FINALISER
// clear FTBs
memset(MP_STATE_MEM(gc_finaliser_table_start), 0, gc_finaliser_table_byte_len);
#endif
// Clear ATBs & finalisers (if enabled). This also clears the extra byte
// which appears between ATBs and finalisers that ensures every chain in
// the ATB terminates, rather than erroneously using bits from the
// finalisers.
memset(MP_STATE_MEM(gc_alloc_table_start), 0, MP_STATE_MEM(gc_pool_start) - MP_STATE_MEM(gc_alloc_table_start));
// Set first free ATB index to the start of the heap.
for (size_t i = 0; i < MICROPY_ATB_INDICES; i++) {

12
shared/libc/string0.c
View File

@ -28,6 +28,8 @@
#include <stddef.h>
#include <string.h>
#include "py/mpconfig.h"
#ifndef likely
#define likely(x) __builtin_expect((x), 1)
#endif
@ -35,6 +37,7 @@
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-align"
void *memcpy(void *dst, const void *src, size_t n) {
#if CIRCUITPY_FULL_BUILD
if (likely(!(((uintptr_t)dst) & 3) && !(((uintptr_t)src) & 3))) {
// pointers aligned
uint32_t *d = dst;
@ -56,7 +59,9 @@ void *memcpy(void *dst, const void *src, size_t n) {
// copy byte
*((uint8_t*)d) = *((const uint8_t*)s);
}
} else {
} else
#endif
{
// unaligned access, copy bytes
uint8_t *d = dst;
const uint8_t *s = src;
@ -93,6 +98,7 @@ void *memmove(void *dest, const void *src, size_t n) {
}
void *memset(void *s, int c, size_t n) {
#if CIRCUITPY_FULL_BUILD
if (c == 0 && ((uintptr_t)s & 3) == 0) {
// aligned store of 0
uint32_t *s32 = s;
@ -106,7 +112,9 @@ void *memset(void *s, int c, size_t n) {
if (n & 1) {
*((uint8_t*)s32) = 0;
}
} else {
} else
#endif
{
uint8_t *s2 = s;
for (; n > 0; n--) {
*s2++ = c;