; Pat80 Memory Monitor ; @author Daniele Verducci ; ; Monitor commands (CMD $arg): ; H (HELP) Shows available commands ; D (DUMP) $pos Dumps 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 ; A (ADB) Enters in Assembly Depoy Bridge mode: loads all the incoming bytes in application memory and starts executing. ; The commands are entered with a single letter and the program completes the command include 'libs/strings.asm' ; CONSTANTS MON_WELCOME: DB 10,"PAT80 MEMORY MONITOR 0.2",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_ZERO: DB "ZERO",0 MON_COMMAND_LOAD: DB "LOAD",0 MON_COMMAND_RUN: DB "RUN",0 MON_COMMAND_ADB: DB "ADB",0 MON_ARG_HEX: DB " 0x",0 MON_HELP: DB 10,"Available commands:\nHELP prints this message\nDUMP [ADDR] shows memory content\nSET [ADDR] sets memory content\nZERO [ADDR] [ADDR] sets all bytes to 0 in the specified range\nLOAD\nRUN [ADDR] executes code starting from ADDR\nADB starts Assembly Deploy Bridge",0 MON_MSG_ADB: DB 10,"Waiting for data.",0 MON_ERR_SYNTAX: DB " Syntax error",0 ;MON_ADB_TIMEOUT: EQU 0xFF // Number of cycles after an ADB binary transfer is considered completed MON_DUMP_BYTES_LINES: EQU 8 MON_DUMP_BYTES_PER_LINE: EQU 8 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_ZERO cp (hl) jp z, monitor_zero 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_ADB cp (hl) jp z, monitor_adb ; 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 ; Asks the user for a memory position and shows the following 64 bytes of memory ; @uses a, b, c, d, e, h, l monitor_dump: ld bc, MON_COMMAND_DUMP + 1 ; autocomplete command call Print ; Now read the address from the user call monitor_arg_2byte ; returns the read bytes in hl ld a, 10 ; newline call Printc ; now start displaying bytes from memory ld e, MON_DUMP_BYTES_LINES ; the number of lines to display monitor_dump_show_bytes_loop: ld d, MON_DUMP_BYTES_PER_LINE*2 ; the number of bytes per line to display (*2 as we display two times the same byte: once hex and once ascii) ; Print current address ld a, h call monitor_printHexByte ld a, l call monitor_printHexByte ; print four spaces ld a, 32 call Printc call Printc call Printc call Printc monitor_dump_show_bytes_line_loop: ; counts down from 15 to 0 ld a, d sub MON_DUMP_BYTES_PER_LINE + 1 jp m, monitor_dump_show_bytes_line_loop_ascii ; jp if ; if position is 8 to 15, print hex value at mem position ld a, (hl) ; print hex byte call monitor_printHexByte ; print space ld a, 32 call Printc ; if position is 4, print a second space (to group nibbles) ld a, d cp MON_DUMP_BYTES_PER_LINE / 2 + MON_DUMP_BYTES_PER_LINE + 1 jp nz, no_second_space ; print second space ld a, 32 call Printc no_second_space: ; move to next mem position inc hl ; decrement "nth byte on the line" counter dec d jp monitor_dump_show_bytes_line_loop ; if position is 0 to 7, print ascii monitor_dump_show_bytes_line_loop_ascii: ; is this the first ascii char printed in this line? ld a, d cp MON_DUMP_BYTES_PER_LINE jp nz, no_mempos_decr ; no need to decrement, already done ; do this only once: printing hex values we advanced the counter by 8 positions. Bring it back. ld bc, MON_DUMP_BYTES_PER_LINE sbc hl, bc ; print 3 spaces to separate hex from ascii ld a, 32 call Printc call Printc call Printc no_mempos_decr: ; print ascii ld a, (hl) call monitor_printAsciiByte ; print space ld a, 32 call Printc ; if position is 12 (8+4), print a second space (to group nibbles) ld a, d cp MON_DUMP_BYTES_PER_LINE / 2 + 1 jp nz, no_second_space2 ; print second space ld a, 32 call Printc no_second_space2: ; move to next mem position inc hl ; decrement counter: if non zero continue loop dec d jp nz, monitor_dump_show_bytes_line_loop ; print newline ld a, 10 call Printc ; decrement line counter dec e jp nz, monitor_dump_show_bytes_loop ; if line counter is not 0, print another line ; if line counter 0, finished jp monitor_main_loop ; Asks user for a memory position and a byte and puts the byte in memory ; @uses a, b, c, h, l monitor_set: ld bc, MON_COMMAND_SET + 1 ; autocomplete command call Print ; Now read the memory address to be changed from the user call monitor_arg_2byte ; returns the read bytes in hl ; Start looping memory addresses monitor_set_byte_loop: ld a, 10 ; newline call Printc ; Print current address ld a, h call monitor_printHexByte ld a, l call monitor_printHexByte ; print two spaces ld a, 32 call Printc call Printc ; print previous memory content (hex) ld a, (hl) call monitor_printHexByte ; print two spaces ld a, 32 call Printc call Printc ; print previous memory content (ascii) ld a, (hl) call monitor_printAsciiByte ; print space ld a, 32 call Printc ; ask the user the new memory content call monitor_arg_byte ; returns the read byte in a, exit code in b ; find if user pressed Q/ENTER ld c, a ; save a ld a, b ; exit code in a cp 1 ; check if user pressed Q jp z, monitor_main_loop ; user wants to exit ld a, b cp 2 ; check if user pressed ENTER jp z, monitor_set_skipbyte ; user doesn't want to replace current byte: skip ; user didn't press Q/ENTER: he inserted a valid byte ; print two spaces ld a, 32 call Printc call Printc ld a, c ; restore valid byte in a call monitor_printAsciiByte ; print user-inserted byte in ascii ld a, c ; restore valid byte in a ld (hl), a ; write new byte to memory monitor_set_skipbyte: inc hl ; next memory position jp monitor_set_byte_loop ; Asks user for a memory range and sets all bytes to zero in that range in memory ; @uses a, b, c, h, l monitor_zero: ; TODO: bugged, doesn't exit cycle ld bc, MON_COMMAND_ZERO + 1 ; autocomplete command call Print ; Now read the starting memory address call monitor_arg_2byte ; returns the read bytes in hl ; starting addr in bc ld b, h ld c, l call monitor_arg_2byte ; ending addr in hl ; Start looping memory addresses (from last to first) monitor_zero_loop: ld (hl), 0 ; set byte to 0 in memory dec hl ; next byte ; check if we reached start addr (one byte at time) ld a, b cp h jp nz, monitor_zero_loop ; first byte is different, continue loop ; first byte is equal, check second one ld a, c cp l jp nz, monitor_zero_loop ; second byte is different, continue loop ; reached destination addr: zero the last byte and return ld (hl), 0 ; set byte to 0 in memory ret 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 ; Now read the memory address to be changed from the user call monitor_arg_2byte ; returns the read bytes in hl ld a, 10 ; newline call Printc jp (hl) ; Start executing code monitor_adb: ld bc, MON_COMMAND_ADB + 1 ; autocomplete command call Print ; start copying incoming data to application space call monitor_copyTermToAppMem ;jp APP_SPACE ; Start executing code ld bc, APP_SPACE call Print jp monitor_main_loop ; Prints "0x" and read 1 hex byte (2 hex digits, e.g. 0x8C) ; Can be cancelled with Q/ENTER ; @return a the read byte, b the exit code (0=valid byte in a, 1=Q, 2=ENTER) ; @uses a, b, c monitor_arg_byte: ; Print 0x... prompt ld bc, MON_ARG_HEX call Print ; Read 2 digits call monitor_arg_byte_impl ret ; Prints "0x" and reads 2 hex bytes (4 hex digits e.g. 0x3F09) ; Ignores Q/ENTER keys ; @return hl the two read bytes ; @uses a, b, c, h, l monitor_arg_2byte: ; Print 0x... prompt ld bc, MON_ARG_HEX call Print ; Read 2 digits call monitor_arg_byte_impl ld h, a ; move result to h ; Read 2 digits call monitor_arg_byte_impl ld l, a ; move result to l ret ; Read 2 hex digits ; @return a the read byte, b the exit code ; (0 if no control key was, pressed, 1 for Q, 2 for RETURN) ; @uses a, b, c monitor_arg_byte_impl: ; Receive first hex digit. Value in a, exit code in b call monitor_readHexDigit ; check exit code to find if user pressed esc or return ld c, a ; save a ld a, b ; load exit code in a cp 0 jp nz, monitor_arg_byte_impl_exitcode ; user pressed Q/RETURN key ; user didn't press Q/RETURN: returned nibble is valid ld a, c ; restore a and discard c ; First hex digit is the most signif nibble, so rotate left by 4 bits rlca rlca rlca rlca ; the lower nibble must now be discarded and %11110000 ld c, a ; save shifted nibble in c ; Read second hex digit call monitor_readHexDigit ; Join the two nibbles in a single byte: second digit is already in a, ; so we OR with the previously shifted c and obtain the complete byte in a. or c ret monitor_arg_byte_impl_exitcode: ; user pressed Q/RETURN key. Exit code is now in a. ld b, a ; move exit code in b ld a, 0 ; clear a ret ; Reads an hex digit (0 to 9, A to F) ; @return a the read nibble (or 0 if Q/RETURN was pressed), b the exit code ; (0 if no control key was, pressed, 1 for Q, 2 for RETURN) ; @uses a, b monitor_readHexDigit: call Readc ; check if user pressed Q ; if user pressed Q, return exit code 1 in b and 0 in a cp 81 jp z, monitor_readHexDigit_esc ; check if user pressed RETURN ; if user pressed RETURN, return exit code 2 in b and 0 in a cp 10 jp z, monitor_readHexDigit_return ; 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 ld b, 0 ; set b to exit code 0 to represent "valid value in a" 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 ld b, 0 ; set b to exit code 0 to represent "valid value in a" ret monitor_readHexDigit_esc: ld a, 0 ld b, 1 ret monitor_readHexDigit_return: ld a, 0 ld b, 2 ret ; Prints a byte in hex format: splits it in two nibbles and prints the two hex digits ; NOTE: The byte in a will be modified! ; @param a the byte to print ; @uses a, b, c monitor_printHexByte: ld c, a ; rotate out the least significant nibble to obtain a byte with the most significant nibble ; in the least significant nibble position rrca a rrca a rrca a rrca a ; the upper nibble must now be discarded and %00001111 call monitor_printHexDigit ld a, c and %00001111 ; bitwise and: set to 0 the most significant nibble and preserve the least call monitor_printHexDigit ret ; Prints an hex digit ; @param a provides the byte containing, in the LSBs, the nibble to print ; @uses a, b monitor_printHexDigit: ; check the input is valid (0 to 15) ld b, a sub 16 ; subtract 16 instead of 15 cause 0 is positive ; if positive, the input is invalid. Do not print anything. ret p ; now check if the digit is a letter (10 to 15 -> A to F) ld a, b ; restore a sub 10 ; if a is positive, the digit is a letter jp p, monitor_printHexDigit_letter ld a, b ; restore a ; add 48 (the ASCII number for 0) to obtain the corresponding number add 48 call Printc ret monitor_printHexDigit_letter: ld a, b ; restore a ; to obtain the corresponding letter we should subtract 10 (so we count from A) ; and add 65 (the ASCII number for A). So -10+65=+55 we add only 55. add 55 call Printc ret ; Prints an ASCII character. Similar to system Print function, but ; ignores control characters and replaces any non-printable character with a dot. ; NOTE: the a register is modified ; @param a the byte to print ; @uses a, b monitor_printAsciiByte: ld b, a ; save a (it will be modified) ; if < 32 is a control char, non printable sub 32 jp m, monitor_printAsciiByte_nonprintable ld a, b ; restore a ; if >= 127 is an extended char, may not be printable sub 127 jp p, monitor_printAsciiByte_nonprintable ; otherwise is a printable ascii char ld a, b ; restore a call Printc ret monitor_printAsciiByte_nonprintable: ld a, 46 ; print dot call Printc ret ; Copy data from STDIN to application memory. This is tought to be used with parallel terminal, not keyboard: ; 0s are not ignored and the sequence is complete when no data is available for 8 cpu cycles. monitor_copyTermToAppMem: ld hl, APP_SPACE ; we will write in APP_SPACE ld b, 255; MON_ADB_TIMEOUT ; the timeout counter (number cycles without available data that represent the end of stream) monitor_copyTermToAppMem_loop: dec b ; decrement the timeout counter ret 0 ; if counter is 0, timeout reached: return ; check if bytes are available call Term_availb cp 0 jp z, monitor_copyTermToAppMem ; no bytes available, next loop ; bytes are available ld b, 255 ;MON_ADB_TIMEOUT; reset the counter ld (hl), a ; copy byte to memory inc hl ; move to next memory position jp monitor_copyTermToAppMem_loop ; continue loop