monitor: handle shift and caps keys

monitor/console.asm

@@ -14,6 +14,7 @@ print_string_to_monitor_loop:
     inc r3
     cmp.8 [r3], 0x00
     ifnz jmp print_string_to_monitor_loop
+    call redraw_monitor_console_line
     pop r3
     pop r0
     ret
@@ -30,10 +31,12 @@ print_character_to_monitor:
 
     cmp.8 r0, 0     ; null
     ifz jmp print_character_to_monitor_end
-    cmp.8 r0, 13    ; carriage return
+    cmp.8 r0, 8     ; backspace
-    ifz jmp print_character_to_monitor_cr
+    ifz jmp print_character_to_monitor_bs
     cmp.8 r0, 10    ; line feed
     ifz jmp print_character_to_monitor_lf
+    cmp.8 r0, 13    ; carriage return
+    ifz jmp print_character_to_monitor_cr
 
     ; check if we are at the end of this line
     cmp.8 [MONITOR_CONSOLE_X], MONITOR_CONSOLE_X_SIZE
@@ -69,6 +72,11 @@ print_character_to_monitor_lf:
     cmp.8 [MONITOR_CONSOLE_Y], MONITOR_CONSOLE_Y_SIZE
     ifgteq call scroll_monitor_console
     call redraw_monitor_console
+    jmp print_character_to_monitor_end
+print_character_to_monitor_bs:
+    ; go back one character
+    cmp.8 [MONITOR_CONSOLE_X], 0
+    ifnz dec.8 [MONITOR_CONSOLE_X]
 print_character_to_monitor_end:
     pop r2
     pop r1

monitor/keyboard.asm

@@ -6,19 +6,56 @@
 ; outputs:
 ; r0: ASCII character
 scancode_to_ascii:
-    add r0, scancode_table
+    push r1
+
+    mov r1, scancode_table
+    bts [MODIFIER_BITMAP], 0
+    ifnz mov r1, scancode_table_shift
+    bts [MODIFIER_BITMAP], 1
+    ifnz mov r1, scancode_table_caps
+    add r0, r1
     movz.8 r0, [r0]
 
+    pop r1
+    ret
+
+; set bit 0 in the modifier bitmap
+; inputs:
+; none
+; outputs:
+; none
+shift_pressed:
+    bse [MODIFIER_BITMAP], 0
+
+    ret
+
+; clear bit 0 in the modifier bitmap
+; inputs:
+; none
+; outputs:
+; none
+shift_released:
+    bcl [MODIFIER_BITMAP], 0
+
+    ret
+
+; toggle bit 1 in the modifier bitmap
+; inputs:
+; none
+; outputs:
+; none
+caps_pressed:
+    bts [MODIFIER_BITMAP], 1
+    ifz bse [MODIFIER_BITMAP], 1
+    ifnz bcl [MODIFIER_BITMAP], 1
+
     ret
 
 ; scancode set 1:
 ; https://wiki.osdev.org/PS/2_Keyboard#Scan_Code_Set_1
-const LSHIFT_PRESS:   0x2A
+const LSHIFT: 0x2A
-const LSHIFT_RELEASE: 0xAA
+const RSHIFT: 0x36
-const RSHIFT_PRESS:   0x36
+const CAPS:   0x3A
-const RSHIFT_RELEASE: 0xB6
-const CAPS_PRESS:     0x3A
-const CAPS_RELEASE:   0xBA
 scancode_table:
     data.8 0 data.8 27 data.str "1234567890-=" data.8 8
     data.8 9 data.str "qwertyuiop[]" data.8 10 data.8 0
@@ -59,4 +96,4 @@ scancode_table_caps:
     data.8 0 data.8 0 data.8 0 data.8 0
     data.8 0 data.8 0 data.8 0
 
-const MONITOR_MODIFIER_BITMAP: 0x03ED3FDB ; 1 byte
+const MODIFIER_BITMAP: 0x03ED36C9 ; 1 byte

monitor/monitor.asm

@@ -2,13 +2,10 @@
 
 invoke_monitor:
     ; set the vsync handler to our own and reenable interrupts
-    ; TODO: save the old vsync handler for when the monitor exits!!!
+    mov [MONITOR_OLD_VSYNC_HANDLER], [0x000003FC]
     mov [0x000003FC], monitor_vsync_handler
     ise
 
-    ; set text buffer poinrer to the start of the text buffer
-    mov [MONITOR_TEXT_BUF_PTR], MONITOR_TEXT_BUF_BOTTOM
-
     ; set the X and Y coords of the console text
     mov.8 [MONITOR_CONSOLE_X], 0
     mov.8 [MONITOR_CONSOLE_Y], MONITOR_CONSOLE_Y_SIZE
@@ -49,30 +46,20 @@ invoke_monitor:
     mov r5, 31
     call draw_filled_rectangle_to_overlay
 
-monitor_event_loop:
+    call monitor_shell_start
-    call get_next_event
 
-    ; was a key pressed?
+    ; restore the old vsync handler and exit
-    cmp r0, EVENT_TYPE_KEY_DOWN
+    mov [0x000003FC], [MONITOR_OLD_VSYNC_HANDLER]
-    ifz call key_down_event
-
-    jmp monitor_event_loop
-
-key_down_event:
-    mov r0, r1
-    call scancode_to_ascii
-    call print_character_to_monitor
-    call redraw_monitor_console_line
     ret
 
 info_str: data.str "fox32rom monitor" data.8 0x00
 
     #include "monitor/console.asm"
     #include "monitor/keyboard.asm"
+    #include "monitor/shell.asm"
     #include "monitor/vsync.asm"
 
-const MONITOR_TEXT_BUF_BOTTOM: 0x03ED3FE0 ; 32 characters
+const MONITOR_OLD_VSYNC_HANDLER: 0x03ED36C6 ; 4 bytes
-const MONITOR_TEXT_BUF_PTR:    0x03ED3FDC ; 4 bytes
 
 const MONITOR_BACKGROUND_COLOR: 0xFF282828
 

monitor/shell.asm

@@ -0,0 +1,136 @@
+; 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
+
+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
+
+    ; otherwise, add it to the text buffer and print it to the screen
+    call scancode_to_ascii
+    call print_character_to_monitor
+    call monitor_shell_push_character
+    call redraw_monitor_console_line
+    ret
+monitor_shell_key_down_event_enter:
+    mov r0, 10 ; line feed
+    call print_character_to_monitor
+    call monitor_shell_parse_line
+    call monitor_shell_clear_buffer
+    mov r0, monitor_shell_prompt
+    call print_string_to_monitor
+    ret
+monitor_shell_key_down_event_backspace:
+    ; delete the last character from the screen, and pop the last character from the buffer
+    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 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:
+    ret
+
+; 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
+const MONITOR_SHELL_TEXT_BUF_PTR:    0x03ED3FDC ; 4 bytes
+
+monitor_shell_prompt: data.str "> " data.8 0