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Reduce duplication in crt0.s

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Couldn't move the interrupt setup though :/. Not sure why
This commit is contained in:
Gwilym Kuiper 2021-06-26 23:00:10 +01:00
parent ccb0e69ff3
commit 7e3b983e80
1 changed files with 16 additions and 41 deletions
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57
agb/crt0.s
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@ -22,31 +22,7 @@ b .Initialise_mb
ldr r1, =0x03007FFC ldr r1, =0x03007FFC
str r0, [r1] str r0, [r1]
@ copies iwram section in ewram to iwram b .CommonInit
ldr r0, =__iwram_rom_start @ load memory address storing start of data for iwram in rom
ldr r1, =__iwram_data_start @ load memory address storing location of iwram in ram
ldr r2, =__iwram_rom_length_halfwords @ load number of 16 bit values to copy
swi 0x000B0000 @ call interrupt CpuSet.
@ r0: source
@ r1: destination
@ r2: length + size information
@
@ see: https://mgba-emu.github.io/gbatek/#swi-0bh-gbands7nds9dsi7dsi9---cpuset
@ everything is in ewram so it is already there, no need to copy that bit
@ put zero in both r0 and r1
@ This corresponds to zero for argc and argv (which would technically be required for a c runtime)
ldr r0, =0
mov r1, r0
@ load main and branch
ldr r2, =main
bx r2
@ loop if we end up here
1:
b 1b
.Initialise: .Initialise:
@ Set interrupt handler @ Set interrupt handler
@ -54,24 +30,23 @@ b .Initialise_mb
ldr r1, =0x03007FFC ldr r1, =0x03007FFC
str r0, [r1] str r0, [r1]
@ copies iwram section in rom to iwram in ram
ldr r0, =__iwram_rom_start @ load memory address storing start of data for iwram in rom
ldr r1, =__iwram_data_start @ load memory address storing location of iwram in ram
ldr r2, =__iwram_rom_length_halfwords @ load number of 16 bit values to copy
swi 0x000B0000 @ call interrupt CpuSet.
@ r0: source
@ r1: destination
@ r2: length + size information
@
@ see: https://mgba-emu.github.io/gbatek/#swi-0bh-gbands7nds9dsi7dsi9---cpuset
@ copies ewram section in rom to ewram in ram @ copies ewram section in rom to ewram in ram
ldr r0, =__ewram_rom_start ldr r0, =__ewram_rom_start @ load memory address storing start of data for ewram in rom
ldr r1, =__ewram_data_start ldr r1, =__ewram_data_start @ load memory address storing location of ewram in ram
ldr r2, =__ewram_rom_length_halfwords ldr r2, =__ewram_rom_length_halfwords @ load number of 16 bit values to copy
swi 0x000B0000 swi 0x000B0000 @ call interrupt CpuSet.
@ r0: source
@ r1: destination
@ r2: length + size information
@
@ see: https://mgba-emu.github.io/gbatek/#swi-0bh-gbands7nds9dsi7dsi9---cpuset
.CommonInit:
@ copies iwram section in rom to iwram in ram
ldr r0, =__iwram_rom_start
ldr r1, =__iwram_data_start
ldr r2, =__iwram_rom_length_halfwords
swi 0x000B0000
@ put zero in both r0 and r1 @ put zero in both r0 and r1
@ This corresponds to zero for argc and argv (which would technically be required for a c runtime) @ This corresponds to zero for argc and argv (which would technically be required for a c runtime)