mirror of
https://github.com/Qyriad/fusee-launcher.git
synced 2024-11-01 04:25:09 +01:00
57 lines
1.0 KiB
ArmAsm
57 lines
1.0 KiB
ArmAsm
//
|
|
// Payload launcher stub.
|
|
//
|
|
|
|
.globl _start
|
|
|
|
.section ".text"
|
|
_start:
|
|
|
|
// First, we'll need to move ourselves _out_ of the target area.
|
|
// We'll copy down into the start of the IRAM.
|
|
ldr r0, =post_relocation
|
|
ldr r1, =START_OF_IRAM
|
|
ldr r2, =intermezzo_end
|
|
sub r2, r2, r0
|
|
bl copy
|
|
|
|
// Jump to the start of RAM, which should now contain the post-relocation code.
|
|
ldr r0, =START_OF_IRAM
|
|
bx r0
|
|
|
|
|
|
.align 4
|
|
post_relocation:
|
|
|
|
// Next, we'll copy our payload down to the appropriate relocaiton address.
|
|
ldr r0, =LOAD_BLOCK_START
|
|
ldr r1, =RELOCATION_TARGET
|
|
ldr r2, =LOAD_BLOCK_LENGTH
|
|
bl copy
|
|
|
|
// Finally, jump into the relocated target.
|
|
ldr r0, =RELOCATION_TARGET
|
|
bx r0
|
|
|
|
|
|
//
|
|
// Simple block copy.
|
|
// r0 = source address
|
|
// r1 = destination address
|
|
// r2 = length in bytes
|
|
// Destroys r3.
|
|
//
|
|
copy:
|
|
|
|
// Copy the word...
|
|
ldr r3, [r0], #4
|
|
str r3, [r1], #4
|
|
|
|
// And continue while we have words left to copy.
|
|
subs r2, r2, #4
|
|
bne copy
|
|
|
|
// Once we're done, return.
|
|
bx lr
|
|
|