pato-z80-home-computer/assembly/bios/monitor.asm
2020-11-25 19:39:20 +01:00

93 lines
2.5 KiB
NASM

; Pat80 Memory Monitor
; @author Daniele Verducci
;
; Monitor commands (CMD $arg):
; H (HELP) Shows available commands
; D (DUMP) $pos Dumps first 100 bytes of memory starting at $pos
; S (SET) $pos $val Replaces byte at $pos with $val
; L (LOAD) $pos $val Loads all the incoming bytes in memory starting from $pos
; R (RUN) $pos Starts executing code from $pos
; The commands are entered with a single letter and the program completes the command
include 'libs/strings.asm'
; CONSTANTS
; All monitor commands are 3 chars long.
MON_WELCOME: DB "PAT80 MEMORY MONITOR 0.1",10,0
MON_COMMAND_HELP: DB "HELP",0 ; null terminated strings
MON_COMMAND_DUMP: DB "DUMP",0
MON_COMMAND_SET: DB "SET",0
MON_COMMAND_LOAD: DB "LOAD",0
MON_COMMAND_RUN: DB "RUN",0
MON_ARG_HEX: DB "0x",0
MON_HELP: DB 10,"Available commands: HELP, DUMP, SET, LOAD, RUN",0
MON_ERR_SYNTAX: DB " Syntax error",0
Monitor_main:
; Print welcome string
ld bc, MON_WELCOME
call Print
monitor_main_loop:
; Newline
ld a, 10
call Printc
; Draw prompt char
ld a, 62 ; >
call Printc
; Read char from command line
call Readc ; blocking: returns when a character was read and placed in A reg
call Strings_charToUpper ; user may enter lowercase char: transform to upper
call Printc ; Print back the character to provide user feedback
; Switch case
ld hl, MON_COMMAND_HELP
cp (hl) ; check incoming char is equal to command's first char
jp z, monitor_help
ld hl, MON_COMMAND_DUMP
cp (hl)
jp z, monitor_dump
ld hl, MON_COMMAND_SET
cp (hl)
jp z, monitor_set
ld hl, MON_COMMAND_LOAD
cp (hl)
jp z, monitor_load
ld hl, MON_COMMAND_RUN
cp (hl)
jp z, monitor_run
; Unrecognized command: print error
ld bc, MON_ERR_SYNTAX
call Print
jp monitor_main_loop
monitor_help:
ld bc, MON_COMMAND_HELP + 1 ; autocomplete command
call Print
ld bc, MON_HELP
call Print
jp monitor_main_loop
monitor_dump:
ld bc, MON_COMMAND_DUMP + 1 ; autocomplete command
call Print
jp monitor_main_loop
monitor_set:
ld bc, MON_COMMAND_SET + 1 ; autocomplete command
call Print
jp monitor_main_loop
monitor_load:
ld bc, MON_COMMAND_LOAD + 1 ; autocomplete command
call Print
jp monitor_main_loop
monitor_run:
ld bc, MON_COMMAND_RUN + 1 ; autocomplete command
call Print
jp APP_VAR_SPACE ; Start executing code
jp monitor_main_loop