oldos/help.txt

; Clear the screen and set cursor position to (0, 0)
clear:

; Detect display. Video mode 0 if no display,
; 1 if monochrome display, 2 if colour display
detect_video:

; Print terminated string
;
; DS:SI - Pointer on string
print_string:

; Print symbol
;
; AL - symbol
; print_symbol:

; Reset buffer
; DS:SI - buffer
; CX - Length
reset_buffer:

; Input string
;
; DS:SI - Pointer on buffer
; CX - Buffer length
; ---
; AX - Last pressed key
input_string:

; Compare strings
;
; DS:SI - Pointer on first string
; DS:BX - Pointer on second string
; ---
; Carry flag - 1 if strings are not equal
compare_strings:

; Copies string
;
; DS:SI - Pointer on memory from where copy
; DS:BX - Pointer on memory where copy
copy_string:

; Calculate len of string
;
; DS:SI - Pointer on string
; ---
; AX - Len of string
calculate_string_len:

; ------------------------------------------------------------------
; os_print_digit -- Displays contents of AX as a single digit
; Works up to base 37, ie digits 0-Z
; IN: AX = "digit" to format and print
os_print_digit:

; ------------------------------------------------------------------
; os_print_1hex -- Displays low nibble of AL in hex format
; IN: AL = number to format and print
os_print_1hex:

; Print AL in hex
;
; AL - Number to print
os_print_2hex:

; Print AX in hex
;
; AX - Number to print
print_hex:

; Print values of registers to screen
;
; AX, BX, CX, DX, SI, DI, ES, DS, SS, FLAGS - Registers to print
print_registers:

; ------------------------------------------------------------------
; os_string_to_int -- Convert decimal string to integer value
; IN: SI = string location (max 5 chars, up to '65536')
; OUT: AX = number
string_to_int:

; Convert unsigned int to string
;
; AX - Num to convert
; SI - Where save string
; ---
; SI - Pointer to string with converted num
int_to_string:

; Find file on disk from filename
; BX - filename
; ---
; SI - filename position in table
; CF - 1 if file not exist
find_file:

; Remove file
; BX - filename
; ---
; CF - 1 if file not exist
remove_file:

; Append file to FS table
; AL - Cylinder
; AH - Head
; BL - sector
; BH - Size
; SI - Pointer on name (Max 11 chars)
append_file:

; Rename file in FS table
; SI - Filename
; BX - To what filename change
rename_file:

; Read file and load to memory
; SI - File in FS table
; CX - Where load
load_file:

; Write file and load to memory
; SI - File in FS table
; CX - Where
save_file:

; Write FS table to disk
write_table:

; Copy memory from A to B
; SI - A
; BX - B
; CX - Number of bytes to copy
copy_memory:

; Get cursor position
; ---
; DL - X
; DH - Y
get_cursor_pos:

; Set cursor position
; DL - X
; DH - Y
set_cursor_pos:

; Print values of registers and halt cpu
dbg_halt_cpu:

; Shows goodbye message and stops the CPU
halt_cpu: