fox32rom/monitor/shell.asm

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; debug monitor shell
monitor_shell_start:
mov.8 [MODIFIER_BITMAP], 0
call monitor_shell_clear_buffer
mov r0, monitor_shell_prompt
call print_string_to_monitor
call redraw_monitor_console
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monitor_shell_event_loop:
call get_next_event
; was a key pressed?
cmp r0, EVENT_TYPE_KEY_DOWN
ifz call monitor_shell_key_down_event
; was a key released?
cmp r0, EVENT_TYPE_KEY_UP
ifz call monitor_shell_key_up_event
jmp monitor_shell_event_loop
monitor_shell_key_down_event:
mov r0, r1
cmp.8 r0, LSHIFT
ifz jmp shift_pressed
cmp.8 r0, RSHIFT
ifz jmp shift_pressed
cmp.8 r0, CAPS
ifz jmp caps_pressed
; first, check if enter, delete, or backspace was pressed
cmp.8 r0, 0x1C ; enter
ifz jmp monitor_shell_key_down_event_enter
cmp.8 r0, 0x6F ; delete
ifz jmp monitor_shell_key_down_event_backspace
cmp.8 r0, 0x0E ; backspace
ifz jmp monitor_shell_key_down_event_backspace
; then, overwrite the cursor
mov r1, r0
mov r0, 8 ; backspace character
call print_character_to_monitor
mov r0, r1
; then, add it to the text buffer and print it to the screen
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call scancode_to_ascii
call print_character_to_monitor
call monitor_shell_push_character
; finally, print the cursor and redraw the line
mov r0, '_'
call print_character_to_monitor
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call redraw_monitor_console_line
ret
monitor_shell_key_down_event_enter:
; clear the cursor from the screen
mov r0, 8 ; backspace character
call print_character_to_monitor
mov r0, ' ' ; space character
call print_character_to_monitor
mov r0, 8 ; backspace character
call print_character_to_monitor
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mov r0, 10 ; line feed
call print_character_to_monitor
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mov r0, 0
call monitor_shell_push_character
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call monitor_shell_parse_line
call monitor_shell_clear_buffer
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mov r0, monitor_shell_prompt
call print_string_to_monitor
call redraw_monitor_console
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ret
monitor_shell_key_down_event_backspace:
; check if we are already at the start of the prompt
mov r1, [MONITOR_SHELL_TEXT_BUF_PTR]
cmp r1, MONITOR_SHELL_TEXT_BUF_BOTTOM
iflteq ret
; delete the last character from the screen, draw the cursor, and pop the last character from the buffer
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mov r0, 8 ; backspace character
call print_character_to_monitor
mov r0, ' ' ; space character
call print_character_to_monitor
mov r0, 8 ; backspace character
call print_character_to_monitor
call print_character_to_monitor
mov r0, '_' ; cursor
call print_character_to_monitor
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call monitor_shell_delete_character
call redraw_monitor_console_line
ret
monitor_shell_key_up_event:
mov r0, r1
cmp.8 r0, LSHIFT
ifz jmp shift_released
cmp.8 r0, RSHIFT
ifz jmp shift_released
ret
monitor_shell_parse_line:
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; if the line is empty, just return
cmp.8 [MONITOR_SHELL_TEXT_BUF_BOTTOM], 0
ifz ret
; separate the command from the arguments
; store the pointer to the arguments
mov r0, MONITOR_SHELL_TEXT_BUF_BOTTOM
mov r1, ' '
call monitor_shell_tokenize
mov [MONTIOR_SHELL_ARGS_PTR], r0
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call monitor_shell_parse_command
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ret
; return tokens separated by the specified character
; returns the next token in the list
; inputs:
; r0: pointer to null-terminated string
; r1: separator character
; outputs:
; r0: pointer to next token or zero if none
monitor_shell_tokenize:
cmp.8 [r0], r1
ifz jmp monitor_shell_tokenize_found_token
cmp.8 [r0], 0
ifz mov r0, 0
ifz ret
inc r0
jmp monitor_shell_tokenize
monitor_shell_tokenize_found_token:
mov.8 [r0], 0
inc r0
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ret
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; parse up to 4 arguments into individual strings
; for example, "this is a test" will be converted to
; r0: pointer to "this" data.8 0
; r1: pointer to "is" data.8 0
; r2: pointer to "a" data.8 0
; r3: pointer to "test" data.8 0
; inputs:
; none
; outputs:
; r0: pointer to 1st null-terminated argument, or zero if none
; r1: pointer to 2nd null-terminated argument, or zero if none
; r2: pointer to 3rd null-terminated argument, or zero if none
; r3: pointer to 4th null-terminated argument, or zero if none
monitor_shell_parse_arguments:
push r31
mov r0, [MONTIOR_SHELL_ARGS_PTR]
mov r1, ' '
mov r31, 3
push r0
monitor_shell_parse_arguments_loop:
call monitor_shell_tokenize
push r0
loop monitor_shell_parse_arguments_loop
pop r3
pop r2
pop r1
pop r0
pop r31
ret
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; push a character to the text buffer
; inputs:
; r0: character
; outputs:
; none
monitor_shell_push_character:
push r1
mov r1, [MONITOR_SHELL_TEXT_BUF_PTR]
cmp r1, MONITOR_SHELL_TEXT_BUF_TOP
ifgteq jmp monitor_shell_push_character_end
mov.8 [r1], r0
inc [MONITOR_SHELL_TEXT_BUF_PTR]
monitor_shell_push_character_end:
pop r1
ret
; pop a character from the text buffer and zero it
; inputs:
; none
; outputs:
; r0: character
monitor_shell_delete_character:
push r1
mov r1, [MONITOR_SHELL_TEXT_BUF_PTR]
cmp r1, MONITOR_SHELL_TEXT_BUF_BOTTOM
iflteq jmp monitor_shell_pop_character_end
dec [MONITOR_SHELL_TEXT_BUF_PTR]
movz.8 r0, [r1]
mov.8 [r1], 0
monitor_shell_pop_character_end:
pop r1
ret
; mark the text buffer as empty
; inputs:
; none
; outputs:
; none
monitor_shell_clear_buffer:
push r0
; set the text buffer poinrer to the start of the text buffer
mov [MONITOR_SHELL_TEXT_BUF_PTR], MONITOR_SHELL_TEXT_BUF_BOTTOM
; set the first character as null
mov r0, [MONITOR_SHELL_TEXT_BUF_PTR]
mov.8 [r0], 0
pop r0
ret
const MONITOR_SHELL_TEXT_BUF_TOP: 0x03ED4000
const MONITOR_SHELL_TEXT_BUF_BOTTOM: 0x03ED3FE0 ; 32 characters
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const MONITOR_SHELL_TEXT_BUF_PTR: 0x03ED3FDC ; 4 bytes - pointer to the current input character
const MONTIOR_SHELL_ARGS_PTR: 0x03ED36C5 ; 4 bytes - pointer to the beginning of the command arguments
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monitor_shell_prompt: data.str "> _" data.8 0