pico-sdk/src/rp2_common/pico_mem_ops/mem_ops_aeabi.S

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2.2 KiB
ArmAsm
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2021-01-20 16:44:27 +00:00
/*
* Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
.syntax unified
.cpu cortex-m0plus
.thumb
#include "pico/asm_helper.S"
__pre_init __aeabi_mem_init, 00001
.macro mem_section name
#if PICO_MEM_IN_RAM
.section RAM_SECTION_NAME(\name), "ax"
#else
.section SECTION_NAME(\name), "ax"
#endif
.endm
.equ MEMSET, 0
.equ MEMCPY, 4
.equ MEMSET4, 8
.equ MEMCPY4, 12
.equ MEM_FUNC_COUNT, 4
# NOTE: All code sections are placed in RAM (at the expense of some veneer cost for calls from flash) because
# otherwise code using basic c division operators will require XIP flash access.
.section .data.aeabi_mem_funcs
.global aeabi_mem_funcs, aeabi_mem_funcs_end
.align 2
aeabi_mem_funcs:
.word rom_table_code('M','S')
.word rom_table_code('M','C')
.word rom_table_code('S','4')
.word rom_table_code('C','4')
aeabi_mem_funcs_end:
.section .text
regular_func __aeabi_mem_init
ldr r0, =aeabi_mem_funcs
movs r1, #MEM_FUNC_COUNT
ldr r3, =rom_funcs_lookup
bx r3
# lump them both together because likely both to be used, in which case doing so saves 1 word
# and it only costs 1 word if not
// Note from Run-time ABI for the ARM architecture 4.3.4:
// If there is an attached device with efficient memory copying or clearing operations
// (such as a DMA engine), its device supplement specifies whether it may be used in
// implementations of these functions and what effect such use has on the devices state.
mem_section aeabi_memset_memcpy
wrapper_func __aeabi_memset
// args are backwards
eors r0, r1
eors r1, r0
eors r0, r1
ldr r3, =aeabi_mem_funcs
ldr r3, [r3, #MEMSET]
bx r3
wrapper_func __aeabi_memset4
wrapper_func __aeabi_memset8
// args are backwards
eors r0, r1
eors r1, r0
eors r0, r1
ldr r3, =aeabi_mem_funcs
ldr r3, [r3, #MEMSET4]
bx r3
wrapper_func __aeabi_memcpy4
wrapper_func __aeabi_memcpy8
ldr r3, =aeabi_mem_funcs
ldr r3, [r3, #MEMCPY4]
bx r3
mem_section memset
wrapper_func memset
ldr r3, =aeabi_mem_funcs
ldr r3, [r3, #MEMSET]
bx r3
mem_section memcpy
wrapper_func __aeabi_memcpy
wrapper_func memcpy
ldr r3, =aeabi_mem_funcs
ldr r3, [r3, #MEMCPY]
bx r3