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kernel: Show an error if running on top of an existing kernel

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Ry 2023-01-25 18:13:45 -08:00
parent 94a6a734a4
commit 75a10ffdc3
1 changed files with 25 additions and 0 deletions
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25
kernel/main.asm
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@ -1,5 +1,7 @@
; fox32os kernel
const LOAD_ADDRESS: 0x03000000
const FOX32OS_VERSION_MAJOR: 0
const FOX32OS_VERSION_MINOR: 1
const FOX32OS_VERSION_PATCH: 1
@ -65,6 +67,28 @@ jump_table_end:
entry:
mov rsp, SYSTEM_STACK
; before doing anything, check if we are running on top of an existing instance of the kernel
; we can do this by comparing our load address to the known load address that the bootloader loads us to
; only the high 16 bits are checked
rcall 6
pop r0
mov.16 r0, 0
cmp r0, LOAD_ADDRESS
ifz jmp entry_ok
; if it appears that we're running on top of an existing kernel, then show a messagebox and exit
; call the messagebox routines of the existing kernel
mov r0, 0
mov r1, kernelception_error_str
mov r2, 0
mov r3, 64
mov r4, 64
mov r5, 184
call [0x00000C34] ; new_messagebox
call [0x00000A18] ; end_current_task
rjmp 0
entry_ok:
; clear the background
mov r0, BACKGROUND_COLOR
call fill_background
@ -310,6 +334,7 @@ bottom_bar_str_1: data.str "32" data.8 0
bottom_bar_str_2: data.str " OS version %u.%u.%u " data.8 0
startup_error_str: data.str "fox32 - OS version %u.%u.%u - startup.cfg is invalid!" data.8 0
memory_error_str: data.str "fox32 - OS version %u.%u.%u - not enough memory to perform operation!" data.8 0
kernelception_error_str: data.str "Error: kernelception?" data.8 0
bottom_bar_patterns:
; 1x16 tile
data.32 0xFF674764