pato-z80-home-computer/assembly/bios/monitor.asm
Daniele Verducci su MatissePenguin 41b746525a Refactored ASM, added sound support
2020-12-06 15:51:26 +01:00

166 lines
4.9 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
; R (RUN) $pos Starts executing code from $pos
; I (IMMEDIATE) Loads all the incoming bytes in application memory starting from $pos. When "0" is received 8 times starts executing the loaded code.
; 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_COMMAND_IMMEDIATE: DB "IMMEDIATE",0
MON_ARG_HEX: DB " 0x",0
MON_HELP: DB 10,"Available commands: HELP, DUMP, SET, LOAD, RUN",0
MON_MSG_IMMEDIATE: DB 10,"Waiting for data. 00000000 to execute.",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
ld hl, MON_COMMAND_IMMEDIATE
cp (hl)
jp z, monitor_immediate
; Unrecognized command: print error and beep
ld bc, MON_ERR_SYNTAX
call Print
call Beep
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
call monitor_arg_byte
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_SPACE ; Start executing code
jp monitor_main_loop
monitor_immediate:
ld bc, MON_COMMAND_IMMEDIATE + 1 ; autocomplete command
call Print
; start copying incoming data to application space
monitor_immediate_copyToAppSpace:
ld bc, APP_SPACE
call Readc
ld (bc), a
cp a, 0
;jmp z monitor_immediate_copyToAppSpace ; così esce al primo 0 che trova, ovviamente invece vogliamo aspettare 8 zeri
jp APP_SPACE ; Start executing code
jp monitor_main_loop
monitor_arg_byte:
; Print 0x... prompt
ld bc, MON_ARG_HEX
call Print
; Receive two hex digits
call monitor_readHexDigit
call monitor_readHexDigit
ret
monitor_arg_2byte:
; Print 0x... prompt
ld bc, MON_ARG_HEX
call Print
; Receive four hex digits
call monitor_readHexDigit
call monitor_readHexDigit
call monitor_readHexDigit
call monitor_readHexDigit
ret
monitor_readHexDigit:
call Readc
; check if is a valid hex digit (0-9 -> ascii codes 48 to 57; A-F -> ascii codes 65 to 70)
; first check if is between 0 and F(ascii codes 48 to 70)
ld b, a
sub a, 48
jp m, monitor_readHexDigit ; if negative (s), ascii code is under 48: ignore char
ld a, b
sub a, 71 ; 71 because we want to include 70 and the result must be negative
jp p, monitor_readHexDigit ; if not negative (ns), ascii code is over 70: ignore it
; check if is a valid int (<=57)
ld a, b
sub a, 58
jp p, monitor_readHexDigit_char ; if not negative (ns), maybe is a char
; otherwise is a number! First print for visive feedback
ld a, b
call Printc
; then convert to its value subtracting 48
sub a, 48
ret
monitor_readHexDigit_char:
; check if is A, B, C, D, E, F (ascii codes 65 to 70). We already checked it is less than 70.
ld a, b
sub a, 65
jp m, monitor_readHexDigit ; if negative (s), ascii code is under 65: ignore char
; otherwise is a valid char (A-F). Print for visive feedback
ld a, b
call Printc
; Its numeric value is 10 (A) to 15 (F). To obtain this, subtract 55.
sub a, 55
ret