lifehackerhansol 107675e006
Fix bugs and compilations from toolchain / b9s upgrade (#56)
* Fix date parsing in Makefile

* crt0: clear more interrupts and registers

After boot9strap 1.4 update, without these SDMMC dies.
Also inadvertently fixes a screen init issue that happens from the
aforementioned boot9strap update.

Co-authored-by: profi200 <fd3194@gmx.de>

* Add memcpy reimplementation

* Change link to guide

Plailect restrctured the domains a few years ago; 3ds.guide is now
3ds.hacks.guide, and devkit guide is panda.hacks.guide.

---------

Co-authored-by: profi200 <fd3194@gmx.de>
Co-authored-by: luigoalma <luigoalma@hotmail.com>
2025-03-29 13:11:55 +01:00

73 lines
1.9 KiB
ArmAsm

@ memcpy_arm946e-s - hand written reimplementation of memcpy to be sequential
@ Written in 2019 by luigoalma <luigoalma at gmail dot com>
@ To the extent possible under law, the author(s) have dedicated all copyright and related and neighboring rights to this software to the public domain worldwide. This software is distributed without any warranty.
@ For a copy of CC0 Public Domain Dedication, see <https://creativecommons.org/publicdomain/zero/1.0/>.
.cpu arm946e-s
.arch armv5te
.arm
.section .text.memcpy, "ax", %progbits
.align 2
.global memcpy
.syntax unified
.type memcpy, %function
memcpy:
@ r0 = dest
@ r1 = src
@ r2 = length
@ check if length 0 and return if so
cmp r2, #0
bxeq lr
push {r0,r4-r9,lr}
@ pre-fetch data
pld [r1]
@ alignment check with word size
@ if not aligned but both are in the same misalignment, fix it up
@ otherwise jump to basic loop
orr r12, r0, r1
ands r12, r12, #3
beq .L1
and r4, r0, #3
and r5, r1, #3
cmp r4, r5
bne .L6
rsb r4, r4, #4
.L0:
ldrb r3, [r1], #1
strb r3, [r0], #1
subs r2, r2, #1
popeq {r0,r4-r9,pc}
subs r4, r4, #1
bne .L0
.L1:
@ check if length higher than 32
@ if so, do the 32 byte block copy loop,
@ until there's nothing left or remainder to copy is less than 32
movs r3, r2, LSR#5
beq .L3
.L2:
ldm r1!, {r4-r9,r12,lr}
stm r0!, {r4-r9,r12,lr}
subs r3, r3, #1
bne .L2
ands r2, r2, #0x1F
popeq {r0,r4-r9,pc}
.L3:
@ copy in word size the remaining data,
@ and finish off with basic loop if can't copy all by word size.
movs r3, r2, LSR#2
beq .L6
.L4:
ldr r12, [r1], #4
str r12, [r0], #4
subs r3, r3, #1
bne .L4
ands r2, r2, #0x3
.L5: @ the basic loop
popeq {r0,r4-r9,pc}
.L6:
ldrb r3, [r1], #1
strb r3, [r0], #1
subs r2, r2, #1
b .L5
.size memcpy, .-memcpy