; text rendering routines const TERMINAL_X_SIZE: 40 const TERMINAL_Y_SIZE: 25 const TEXT_COLOR: 0xFFFFFFFF const BACKGROUND_COLOR: 0xFF000000 const FILL_TERM: 0xF0 const MOVE_CURSOR: 0xF1 const REDRAW_LINE: 0xFE const REDRAW: 0xFF ; print a single character to the terminal ; inputs: ; r0: ASCII character or control character ; outputs: ; none print_character_to_terminal: ; if we're in a control state, or the char has the highest bit set ; then handle it as a control character ; allow character 0x8A (the block cursor itself) to pass through cmp.8 r0, 0x8A ifz jmp print_character_to_terminal_allow cmp.8 [terminal_state], 0 ifnz jmp handle_control_character bts r0, 7 ifnz jmp handle_control_character print_character_to_terminal_allow: push r0 push r1 push r2 cmp.8 r0, 0 ; null ifz jmp print_character_to_terminal_end cmp.8 r0, 8 ; backspace ifz jmp print_character_to_terminal_bs cmp.8 r0, 10 ; line feed ifz jmp print_character_to_terminal_lf cmp.8 r0, 13 ; carriage return ifz jmp print_character_to_terminal_cr ; check if we are at the end of this line cmp.8 [terminal_x], TERMINAL_X_SIZE ; if so, increment to the next line ifgteq mov.8 [terminal_x], 0 ifgteq inc.8 [terminal_y] ; check if we need to scroll the display cmp.8 [terminal_y], TERMINAL_Y_SIZE ifgteq call scroll_terminal ; calculate coords for character... movz.8 r1, [terminal_x] movz.8 r2, [terminal_y] mul r2, TERMINAL_X_SIZE add r1, r2 add r1, terminal_text_buf ; ...and print!! mov.8 [r1], r0 inc.8 [terminal_x] jmp print_character_to_terminal_end print_character_to_terminal_cr: ; return to the beginning of the line mov.8 [terminal_x], 0 jmp print_character_to_terminal_end print_character_to_terminal_lf: ; draw the line call redraw_terminal_line ; return to the beginning of the line and increment the line mov.8 [terminal_x], 0 inc.8 [terminal_y] ; scroll the display if needed cmp.8 [terminal_y], TERMINAL_Y_SIZE ifgteq call scroll_terminal jmp print_character_to_terminal_end print_character_to_terminal_bs: ; go back one character cmp.8 [terminal_x], 0 ifnz dec.8 [terminal_x] print_character_to_terminal_end: pop r2 pop r1 pop r0 ret ; control character state machine ; inputs: ; r0: control character or parameter ; outputs: ; none handle_control_character: cmp.8 [terminal_state], 0 ; got control character ifz mov.8 [terminal_control_char], r0 ifz mov.8 [terminal_state], 1 ifz ret cmp.8 [terminal_state], 1 ; got first parameter ifz mov.8 [terminal_control_parameter_1], r0 ifz mov.8 [terminal_state], 2 ifz ret cmp.8 [terminal_state], 2 ; got second parameter, now execute ifz mov.8 [terminal_control_parameter_2], r0 ifz mov.8 [terminal_state], 0 ; fill terminal cmp.8 [terminal_control_char], FILL_TERM ifz jmp handle_control_character_fill_term ; set cursor position cmp.8 [terminal_control_char], MOVE_CURSOR ifz jmp handle_control_character_set_cursor_pos ; redraw line cmp.8 [terminal_control_char], REDRAW_LINE ifz jmp handle_control_character_redraw_line ; redraw cmp.8 [terminal_control_char], REDRAW ifz jmp handle_control_character_redraw ret handle_control_character_fill_term: push r0 push r31 mov r0, terminal_text_buf mov r31, 1000 handle_control_character_fill_term_loop: mov.8 [r0], [terminal_control_parameter_1] inc r0 loop handle_control_character_fill_term_loop call redraw_terminal pop r31 pop r0 ret handle_control_character_set_cursor_pos: call redraw_terminal_line mov.8 [terminal_x], [terminal_control_parameter_1] mov.8 [terminal_y], [terminal_control_parameter_2] ret handle_control_character_redraw_line: call redraw_terminal_line ret handle_control_character_redraw: call redraw_terminal ret ; scroll the terminal ; inputs: ; none ; outputs: ; none scroll_terminal: push r0 push r1 push r2 push r31 ; source mov r0, terminal_text_buf add r0, TERMINAL_X_SIZE ; destination mov r1, terminal_text_buf ; size mov r2, TERMINAL_X_SIZE mul r2, 24 div r2, 4 call copy_memory_words mov.8 [terminal_x], 0 mov.8 [terminal_y], 24 ; clear the last line mov r0, terminal_text_buf add r0, 960 ; 40 * 24 mov r31, TERMINAL_X_SIZE scroll_terminal_clear_loop: mov.8 [r0], 0 inc r0 loop scroll_terminal_clear_loop ; redraw the screen call redraw_terminal pop r31 pop r2 pop r1 pop r0 ret ; redraw the whole terminal ; inputs: ; none ; outputs: ; none redraw_terminal: push r0 push r1 push r2 push r3 push r4 push r5 push r6 push r31 mov r0, window_struct call get_window_overlay_number mov r5, r0 mov r0, terminal_text_buf mov r1, 0 mov r2, 16 mov r3, TEXT_COLOR mov r4, BACKGROUND_COLOR mov r31, TERMINAL_Y_SIZE redraw_terminal_loop_y: push r31 mov r1, 0 mov r31, TERMINAL_X_SIZE redraw_terminal_loop_x: push r0 movz.8 r0, [r0] call draw_font_tile_to_overlay movz.8 r0, 8 add r1, r0 pop r0 inc r0 loop redraw_terminal_loop_x pop r31 movz.8 r6, 16 add r2, r6 loop redraw_terminal_loop_y pop r31 pop r6 pop r5 pop r4 pop r3 pop r2 pop r1 pop r0 ret ; redraw only the current line ; inputs: ; none ; outputs: ; none redraw_terminal_line: push r0 push r1 push r2 push r3 push r4 push r5 push r6 push r31 mov r0, window_struct call get_window_overlay_number mov r5, r0 movz.8 r0, [terminal_y] mul r0, TERMINAL_X_SIZE add r0, terminal_text_buf movz.8 r1, [terminal_y] mov r2, 16 mul r2, r1 add r2, 16 mov r1, 0 mov r3, TEXT_COLOR mov r4, BACKGROUND_COLOR mov r1, 0 mov r31, TERMINAL_X_SIZE redraw_terminal_line_loop_x: push r0 movz.8 r0, [r0] call draw_font_tile_to_overlay movz.8 r0, 8 add r1, r0 pop r0 inc r0 loop redraw_terminal_line_loop_x pop r31 pop r6 pop r5 pop r4 pop r3 pop r2 pop r1 pop r0 ret terminal_x: data.8 0 terminal_y: data.8 0 terminal_text_buf: data.fill 0, 1000 ; 40x25 = 1000 bytes terminal_state: data.8 0 ; 0: normal, 1: awaiting first control parameter, 2: awaiting second control parameter terminal_control_char: data.8 0 terminal_control_parameter_1: data.8 0 terminal_control_parameter_2: data.8 0