fox32os/kernel/main.asm

286 lines
7.0 KiB
NASM

; fox32os kernel
const FOX32OS_VERSION_MAJOR: 0
const FOX32OS_VERSION_MINOR: 1
const FOX32OS_VERSION_PATCH: 1
const SYSTEM_STACK: 0x01FFF800
const BACKGROUND_COLOR: 0xFF674764
const TEXT_COLOR: 0xFFFFFFFF
jmp entry
; system jump table
org.pad 0x00000010
jump_table:
data.32 get_os_version
; FXF jump table
org.pad 0x00000110
data.32 parse_fxf_binary
; task jump table
org.pad 0x00000210
data.32 new_task
data.32 yield_task
data.32 end_current_task
data.32 get_current_task_id
data.32 get_unused_task_id
data.32 is_task_id_used
; memory jump table
org.pad 0x00000310
data.32 allocate_memory
data.32 free_memory
; window jump table
org.pad 0x00000410
data.32 new_window
data.32 destroy_window
data.32 new_window_event
data.32 get_next_window_event
data.32 draw_title_bar_to_window
data.32 move_window
data.32 fill_window
data.32 get_window_overlay_number
data.32 start_dragging_window
; VFS jump table
org.pad 0x00000510
data.32 open
data.32 seek
data.32 tell
data.32 read
data.32 write
; shell jump table
org.pad 0x00000610
data.32 new_shell_task
jump_table_end:
; initialization code
entry:
mov rsp, SYSTEM_STACK
; clear the background
mov r0, BACKGROUND_COLOR
call fill_background
; initialize the memory allocator
call initialize_allocator
; draw the startup text
mov r0, startup_str
mov r1, 16
mov r2, 464
mov r3, TEXT_COLOR
mov r4, 0x00000000
mov r10, FOX32OS_VERSION_MAJOR
mov r11, FOX32OS_VERSION_MINOR
mov r12, FOX32OS_VERSION_PATCH
call draw_format_str_to_background
; copy the jump table to 0x00000810
mov r0, jump_table
mov r1, 0x00000810
mov r2, jump_table_end
sub r2, jump_table
call copy_memory_bytes
; check if a disk is inserted as disk 1
; if so, skip checking startup.cfg and just run disk 1
in r31, 0x80001001
cmp r31, 0
ifnz jmp boot_disk_1
; open startup.cfg
mov r0, startup_cfg
mov r1, 0
mov r2, startup_cfg_struct
call ryfs_open
cmp r0, 0
ifz jmp boot_disk_1
; load a startup task
load_startup_task:
; load 11 bytes of startup.cfg into startup_file
mov r0, 11
mov r1, startup_cfg_struct
mov r2, startup_file
call ryfs_read
; open the actual startup file
mov r0, startup_file
mov r1, 0
mov r2, startup_file_struct
call ryfs_open
cmp r0, 0
ifz jmp boot_disk_1
; allocate memory for the startup file
mov r0, startup_file_struct
call ryfs_get_size
call allocate_memory
cmp r0, 0
ifz jmp memory_error
mov [startup_file_binary_ptr], r0
; allocate 64KiB for the startup file's stack
mov r0, 65536
call allocate_memory
cmp r0, 0
ifz jmp memory_error
mov [startup_file_stack_ptr], r0
; read the startup file into memory
mov r0, startup_file_struct
mov r1, [startup_file_binary_ptr]
call ryfs_read_whole_file
; relocate and execute it as a new task
mov r0, r1
call parse_fxf_binary
mov r3, r1
mov r1, r0
movz.8 r0, [next_task_id]
mov r2, [startup_file_stack_ptr]
add r2, 65536
sub r2, 4
mov r4, [startup_file_stack_ptr]
call new_task
; when the startup file yields for the first time, we'll end up back here
; now, check to see if startup.cfg has any other entries
; we do this by checking to see if the size of startup.cfg is less than or equal to 12 * next_task_id bytes
inc.8 [next_task_id]
mov r0, startup_cfg_struct
call ryfs_get_size
movz.8 r1, [next_task_id]
mul r1, 12
cmp r0, r1
iflteq jmp no_other_tasks
; seek forward one byte to skip the linefeed
mov r0, startup_cfg_struct
call ryfs_tell
inc r0
mov r1, startup_cfg_struct
call ryfs_seek
; load the next task
jmp load_startup_task
no_other_tasks:
; start the event manager task
call start_event_manager_task
; jump back to it without adding this "task" (not really a task) into the queue.
; end_current_task_no_mark_no_free is used specifically because it doesn't mark
; the current task (still set to 0) as unused, and it doesn't free the memory
; block.
; this does not return.
call end_current_task_no_mark_no_free
; if startup.cfg is invalid, try loading the raw contents of disk 1 as an FXF binary
; if disk 1 is not inserted, then fail
boot_disk_1:
; check if a disk is inserted as disk 1
in r31, 0x80001001
cmp r31, 0
ifz jmp startup_error
; a disk is inserted, load it!!
; allocate memory for the startup file
; r31 contains disk size
mov r0, r31
call allocate_memory
cmp r0, 0
ifz jmp memory_error
div r31, 512
inc r31
mov r2, r0 ; destination pointer
mov r5, r0
mov r0, 0 ; sector counter
mov r3, 0x80003001 ; command to read a sector from disk 1 into memory
mov r4, 0x80002000 ; command to set the location of the buffer
boot_disk_1_loop:
out r4, r2 ; set the memory buffer location
out r3, r0 ; read the current sector into memory
inc r0 ; increment sector counter
add r2, 512 ; increment the destination pointer
loop boot_disk_1_loop
mov r1, r5
mov r0, r5
call parse_fxf_binary
mov r3, r1
mov r1, r0
movz.8 r0, [next_task_id]
mov r2, rsp
sub r2, 4
mov r4, 0 ; don't attempt to free any stack block if the task ends
call new_task
jmp no_other_tasks
startup_error:
mov r0, BACKGROUND_COLOR
call fill_background
mov r0, startup_error_str
mov r1, 16
mov r2, 464
mov r3, TEXT_COLOR
mov r4, 0x00000000
mov r10, FOX32OS_VERSION_MAJOR
mov r11, FOX32OS_VERSION_MINOR
mov r12, FOX32OS_VERSION_PATCH
call draw_format_str_to_background
rjmp 0
memory_error:
mov r0, BACKGROUND_COLOR
call fill_background
mov r0, memory_error_str
mov r1, 16
mov r2, 464
mov r3, TEXT_COLOR
mov r4, 0x00000000
mov r10, FOX32OS_VERSION_MAJOR
mov r11, FOX32OS_VERSION_MINOR
mov r12, FOX32OS_VERSION_PATCH
call draw_format_str_to_background
rjmp 0
get_os_version:
mov r0, FOX32OS_VERSION_MAJOR
mov r1, FOX32OS_VERSION_MINOR
mov r2, FOX32OS_VERSION_PATCH
ret
#include "allocator.asm"
#include "fxf/fxf.asm"
#include "shell/shell.asm"
#include "task.asm"
#include "window/window.asm"
#include "vfs.asm"
startup_str: data.str "fox32 - 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
next_task_id: data.8 0
startup_cfg: data.str "startup cfg"
startup_cfg_struct: data.32 0 data.32 0
startup_file: data.str " "
startup_file_struct: data.32 0 data.32 0
startup_file_binary_ptr: data.32 0
startup_file_stack_ptr: data.32 0
#include "../../fox32rom/fox32rom.def"
kernel_bottom: