310 lines
6.9 KiB
NASM
310 lines
6.9 KiB
NASM
; shell routines
|
|
|
|
const CURSOR: 138
|
|
|
|
; create a new shell task
|
|
; inputs:
|
|
; r0: task ID
|
|
; r1: pointer to stream struct
|
|
; outputs:
|
|
; none
|
|
new_shell_task:
|
|
push r0
|
|
push r1
|
|
push r2
|
|
push r3
|
|
push r4
|
|
push r10
|
|
|
|
; allocate a 64KiB stack and push the pointer to the stream struct to it
|
|
push r0
|
|
push r1
|
|
mov r0, 65536
|
|
call allocate_memory
|
|
add r0, 65532
|
|
pop r1
|
|
mov [r0], r1
|
|
mov r10, r0
|
|
pop r0
|
|
|
|
; then start the task
|
|
mov r1, shell_task ; initial instruction pointer
|
|
mov r2, r10 ; initial stack pointer
|
|
mov r3, 0 ; pointer to task code block to free when task ends
|
|
; (zero since we don't want to free any code blocks when the task ends)
|
|
mov r4, r10 ; pointer to task stack block to free when task ends
|
|
sub r4, 65536 ; point to the start of the stack block that we allocated above
|
|
call new_task
|
|
|
|
pop r10
|
|
pop r4
|
|
pop r3
|
|
pop r2
|
|
pop r1
|
|
pop r0
|
|
ret
|
|
|
|
; print a character to the terminal
|
|
; inputs:
|
|
; r0: ASCII character
|
|
; outputs:
|
|
; none
|
|
print_character_to_terminal:
|
|
push r1
|
|
push r2
|
|
|
|
mov.8 [shell_char_buffer], r0
|
|
mov r1, [shell_terminal_stream_struct_ptr]
|
|
mov r2, shell_char_buffer
|
|
call write
|
|
|
|
pop r2
|
|
pop r1
|
|
ret
|
|
|
|
; print a string to the terminal
|
|
; inputs:
|
|
; r0: pointer to null-terminated string
|
|
; outputs:
|
|
; none
|
|
print_str_to_terminal:
|
|
push r0
|
|
push r2
|
|
|
|
mov r1, [shell_terminal_stream_struct_ptr]
|
|
mov r2, r0
|
|
print_str_to_terminal_loop:
|
|
call write
|
|
inc r2
|
|
cmp.8 [r2], 0x00
|
|
ifnz jmp print_str_to_terminal_loop
|
|
|
|
pop r2
|
|
pop r0
|
|
ret
|
|
|
|
shell_task:
|
|
pop [shell_terminal_stream_struct_ptr]
|
|
shell_task_return:
|
|
call shell_clear_buffer
|
|
call shell_print_prompt
|
|
shell_task_loop:
|
|
mov r1, [shell_terminal_stream_struct_ptr]
|
|
mov r2, shell_char_buffer
|
|
call read
|
|
|
|
movz.8 r0, [shell_char_buffer]
|
|
cmp.8 r0, 0
|
|
ifnz call shell_task_parse_key
|
|
|
|
call yield_task
|
|
rjmp shell_task_loop
|
|
|
|
shell_task_parse_key:
|
|
; first, check if enter, delete, or backspace was pressed
|
|
cmp.8 r0, 0x1C ; enter
|
|
ifz jmp shell_key_down_enter
|
|
cmp.8 r0, 0x6F ; delete
|
|
ifz jmp shell_key_down_backspace
|
|
cmp.8 r0, 0x0E ; backspace
|
|
ifz jmp shell_key_down_backspace
|
|
|
|
; then, overwrite the cursor
|
|
mov r1, r0
|
|
mov r0, 8 ; backspace character
|
|
call print_character_to_terminal
|
|
mov r0, r1
|
|
|
|
; then, add it to the text buffer and print it to the screen
|
|
call scancode_to_ascii
|
|
call print_character_to_terminal
|
|
call shell_push_character
|
|
|
|
; finally, print the cursor
|
|
mov r0, CURSOR
|
|
call print_character_to_terminal
|
|
ret
|
|
shell_key_down_enter:
|
|
; clear the cursor from the screen
|
|
mov r0, 8 ; backspace character
|
|
call print_character_to_terminal
|
|
mov r0, ' ' ; space character
|
|
call print_character_to_terminal
|
|
mov r0, 8 ; backspace character
|
|
call print_character_to_terminal
|
|
|
|
mov r0, 10 ; line feed
|
|
call print_character_to_terminal
|
|
|
|
mov r0, 0
|
|
call shell_push_character
|
|
|
|
call shell_parse_line
|
|
call shell_clear_buffer
|
|
|
|
call shell_print_prompt
|
|
ret
|
|
shell_key_down_backspace:
|
|
; check if we are already at the start of the prompt
|
|
mov r1, [shell_text_buf_ptr]
|
|
cmp r1, shell_text_buf_bottom
|
|
iflteq ret
|
|
; delete the last character from the screen, draw the cursor, and pop the last character from the buffer
|
|
mov r0, 8 ; backspace character
|
|
call print_character_to_terminal
|
|
mov r0, ' ' ; space character
|
|
call print_character_to_terminal
|
|
mov r0, 8 ; backspace character
|
|
call print_character_to_terminal
|
|
call print_character_to_terminal
|
|
mov r0, CURSOR ; cursor
|
|
call print_character_to_terminal
|
|
call shell_delete_character
|
|
ret
|
|
|
|
shell_print_prompt:
|
|
movz.8 r0, [shell_current_disk]
|
|
add r0, '0'
|
|
call print_character_to_terminal
|
|
mov r0, shell_prompt
|
|
call print_str_to_terminal
|
|
ret
|
|
|
|
shell_parse_line:
|
|
; if the line is empty, just return
|
|
cmp.8 [shell_text_buf_bottom], 0
|
|
ifz ret
|
|
|
|
; separate the command from the arguments
|
|
; store the pointer to the arguments
|
|
mov r0, shell_text_buf_bottom
|
|
mov r1, ' '
|
|
call shell_tokenize
|
|
mov [shell_args_ptr], r0
|
|
|
|
call shell_parse_command
|
|
|
|
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
|
|
shell_tokenize:
|
|
cmp.8 [r0], r1
|
|
ifz jmp shell_tokenize_found_token
|
|
|
|
cmp.8 [r0], 0
|
|
ifz mov r0, 0
|
|
ifz ret
|
|
|
|
inc r0
|
|
jmp shell_tokenize
|
|
shell_tokenize_found_token:
|
|
mov.8 [r0], 0
|
|
inc r0
|
|
ret
|
|
|
|
; 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
|
|
shell_parse_arguments:
|
|
push r31
|
|
|
|
mov r0, [shell_args_ptr]
|
|
mov r1, ' '
|
|
mov r31, 3
|
|
push r0
|
|
shell_parse_arguments_loop:
|
|
call shell_tokenize
|
|
push r0
|
|
loop shell_parse_arguments_loop
|
|
pop r3
|
|
pop r2
|
|
pop r1
|
|
pop r0
|
|
|
|
pop r31
|
|
ret
|
|
|
|
; push a character to the text buffer
|
|
; inputs:
|
|
; r0: character
|
|
; outputs:
|
|
; none
|
|
shell_push_character:
|
|
push r1
|
|
|
|
mov r1, [shell_text_buf_ptr]
|
|
cmp r1, shell_text_buf_top
|
|
ifgteq jmp shell_push_character_end
|
|
mov.8 [r1], r0
|
|
inc [shell_text_buf_ptr]
|
|
shell_push_character_end:
|
|
pop r1
|
|
ret
|
|
|
|
; pop a character from the text buffer and zero it
|
|
; inputs:
|
|
; none
|
|
; outputs:
|
|
; r0: character
|
|
shell_delete_character:
|
|
push r1
|
|
|
|
mov r1, [shell_text_buf_ptr]
|
|
cmp r1, shell_text_buf_bottom
|
|
iflteq jmp shell_delete_character_end
|
|
dec [shell_text_buf_ptr]
|
|
movz.8 r0, [r1]
|
|
mov.8 [r1], 0
|
|
shell_delete_character_end:
|
|
pop r1
|
|
ret
|
|
|
|
; mark the text buffer as empty
|
|
; inputs:
|
|
; none
|
|
; outputs:
|
|
; none
|
|
shell_clear_buffer:
|
|
push r0
|
|
|
|
; set the text buffer poinrer to the start of the text buffer
|
|
mov [shell_text_buf_ptr], shell_text_buf_bottom
|
|
|
|
; set the first character as null
|
|
mov r0, [shell_text_buf_ptr]
|
|
mov.8 [r0], 0
|
|
|
|
pop r0
|
|
ret
|
|
|
|
shell_text_buf_bottom: data.fill 0, 32
|
|
shell_text_buf_top:
|
|
shell_text_buf_ptr: data.32 0 ; pointer to the current input character
|
|
shell_args_ptr: data.32 0 ; pointer to the beginning of the command arguments
|
|
|
|
shell_current_disk: data.8 0
|
|
|
|
shell_prompt: data.str "> " data.8 CURSOR data.8 0
|
|
|
|
shell_terminal_stream_struct_ptr: data.32 0
|
|
shell_char_buffer: data.32 0
|
|
|
|
#include "shell/commands/commands.asm"
|
|
#include "shell/launch.asm"
|