UNSC Text 0.3.2

;UNSC Text Edit V: 0.3.2


;This line enables program to be run standalone
;Usually the OS would set the PC to text edit via its menu or something similar
SET PC, textedit

;this section may not be needed. Purely enables program to run standalone
;Replace the JSR command to reach here (ln 19) with the command to run the OS clear function
:textclear
SET [0x8000+A], 0
ADD A, 1
IFG A, 0x200
SET PC, POP
SET PC, textclear

:textedit
SET PUSH, A
SET PUSH, B
SET PUSH, C
JSR textclear;replace this line with the relevant OS function to clear screen

;Draw header
SET [0x8000],0x0F55;U
SET [0x8001],0x0F4E;N
SET [0x8002],0x0F53;S
SET [0x8003],0x0F43;C
SET [0x8004],0x0F20;
SET [0x8005],0x0F54;T
SET [0x8006],0x0F65;e
SET [0x8007],0x0F78;x
SET [0x8008],0x0F74;t
SET [0x8009],0x0F20;
SET [0x800A],0x0F45;E
SET [0x800B],0x0F64;d
SET [0x800C],0x0F69;i
SET [0x800D],0x0F74;t
SET [0x800E],0x0F20;
SET [0x800F],0x0F56;V
SET [0x8010],0x0F3A;:
SET [0x8011],0x0F20;
SET [0x8012],0x0F30;0  < Major version, 1 on full V1 OS release
SET [0x8013],0x0F2E;.
SET [0x8014],0x0F33;3  < Minor Version
SET [0x8015],0x0F2E;.
SET [0x8016],0x0F32;2  < Patch version, increment by 1 for each patch release


SET [0x8020], 0xF0DF;Sets the blinking cursor for typing with
SET B, 0 ;DO NOT CHANGE, unless you know how to fix the endless bugs it causes

:textedit_loop
SET A, [0x9000]
IFE A, 0x0
SET PC, textedit_loop
IFE A, 0x1B
SET PC, textedit_exit
IFE A, 0xA
SET PC, textedit_newline
IFE A, 8
SET PC, textedit_backspace
IFE A, 1
SET PC, textedit_left
IFE A, 2
SET PC, textedit_right
IFE A, 3
SET PC, textedit_up
IFE A, 4
SET PC, textedit_down
ADD A, 0xF000
SET [0x8020 + B], A
SET [0x9000], 0x0
SET C, A
SET PC, textedit_right

:textedit_newline
SET [0x9000], 0x0
IFG B, 0x1BF
SET PC, textedit_loop
SET [0x8020+B], C
SHR B, 5
SHL B, 5
ADD B, 31
SET C, [0x8020+B]
SET PC, textedit_right

:textedit_backspace
SET [0x9000], 0x0
IFN B, 0x0
SET [0x801F + B], 0x0
SET PC, textedit_left

:textedit_down
SET [0x9000], 0x0
IFG B, 0x1BF
SET PC, textedit_loop
IFN [0x8020+B], C
SET [0x8020+B], C
ADD B, 32
SET C, [0x8020 + B]
IFN [0x8020+B], 0x0
SET PC, textedit_not
IFE [0x8020+B], 0x0
SET PC, textedit_equal

:textedit_up
SET [0x9000], 0x0
IFG 0x20, B
SET PC, textedit_loop
IFN [0x8020+B],C
SET [0x8020+B],C
SUB B, 32
SET C, [0x8020+B]
IFN [0x8020+B], 0x0
SET PC, textedit_not
IFE [0x8020+B], 0x0
SET PC, textedit_equal

:textedit_left
SET [0x9000], 0x0
IFE B, 0
SET PC, textedit_loop
IFN [0x8020+B],C
SET [0x8020+B],C
SUB B, 1
SET C, [0x8020+B]
IFN [0x8020+B], 0x0
SET PC, textedit_not
IFE [0x8020+B], 0x0
SET PC, textedit_equal

:textedit_right
SET [0x9000], 0x0
IFE B, 0x1FF
SET PC, textedit_loop
IFN [0x8020+B], C
SET [0x8020+B], C
ADD B, 1
SET C, [0x8020 + B]
IFN [0x8020+B], 0x0
SET PC, textedit_not
IFE [0x8020+B], 0x0
SET PC, textedit_equal

:textedit_not
SUB [0x8020+B],0xE100
SET PC, textedit_loop

:textedit_equal
SET [0x8020+B],0xF0DF
SET PC, textedit_loop

:textedit_exit
SET C, POP
SET B, POP
SET A, POP
;The registers had to go home ):
:texteditend

;debug
SET PC, texteditend