Monitor version .8 beta.¢¢ General:¢¢Note: 24 bit support, and the full 65816 instruction set are not completed¢yet.¢¢Filenames default to the current drive number which can be changed.¢(input of 'FILE' = 'D1:FILE') A full filespec will override the default.¢¢Non destructive prompt character (.) for ease in full screen editing. Also,¢the prompt does not interfere with command decoding. If the cursor is moved¢up to redo a prior command, the '.' does not need to be deleted.¢¢Upper and Lower case accepted.¢¢Continuous memory displays can be stepped one line at a time with the space¢bar. Press 'C' to return to continuous display. ESC, RETURN, or BREAK will¢stop the display.¢¢ALL addresses and data bytes can be entered in HEX (default), in DECIMAL with¢# (#1234), in binary with % (%10011010), in ASCII with ' ('A) or as a label¢currently defined in the MAE symbol table with . (.LABEL). Arithmetic¢operators +-*/&! can also be used, and will be performed left to right. Any¢combination of these can be mixed at any time in a completely free format¢scheme, with no limits on length. (Ex: 2000-#256+'W/100) Very little will¢be mentioned about this feature later on, but ALL numbers for ALL commands¢accept this versatile entry system.¢¢All commands use spaces as delimiters. A '?' indicates a command error.¢Parameter uses for commands are abbreviated to:¢¢adr: a 16 bit address.¢by: an 8 bit byte. ('by' with numbers indicates a string of bytes.)¢bit: a 0 or a 1.¢char: an ASCII character.¢Quantities in [brackets] are optional parameters. Default values will be¢used if they are not entered. All non-bracketted values must be entered.¢Any other upper case characters or symbols should be entered as stated.¢¢'Current address' refers to the last displayed or changed address, (plus¢one), and is separate from the current program counter or PC.¢¢ COMMANDS:¢¢ Display Memory. M [adr] [adr][/]¢Displays hex and ASCII. Displays 24 locations if only 1 parameter. Displays¢from current adr if no parms. '/' = to $FFFF. The '/' can be used on all¢other commands as well. Does not display ASCII control characters when¢output is being sent to an external device.¢¢ Peek Memory. P adr1 [adr2..] [*]¢Special memory display that allows multiple addresses to be entered, and only¢prints one byte per address. * causes continuous print of list of addresses.¢Push Break to abort.¢¢ Disassemble D [adr]¢Disassembles memory starting at adr, or the current adr if not entered. If¢MAE is resident, the assembly code can be modified using normal screen¢editing. Single line assembly can be started from scratch by typing,¢"-adr ." followed by an assembly mnuemonic. (The '.' is necessary). From¢the single line assembler, you may enter '*' as the first mnuemonic character¢to continue disassembly from that address forward.¢¢ Change Memory. :adr by1 [by2..by8]¢The change memory command ':' can be entered directly, or edited from the¢display memory command. Only 8 data bytes will be changed.¢¢ ASCII Mem Change C adr ASCII STRING¢Stores ASCII string at adr. Addresses for both change memory commands may¢use * for current address. (ex. C 1000 COMPUTER. :* 9B.) The second¢command will put a CR after the ASCII string.¢¢ Display Registers R¢Displays 6502 registers in this form:¢ ,A X Y NV-BDIZC SP¢ ;AB 5D FA 10110001 FF 7014 LDA #$00¢¢ Change Registers ; register bytes¢Supports screen editing of R command. Status flags can be modified in bit¢form. When entering values directly, a comma will skip to the next register,¢and you don't need to enter all the values. EX: ';55' will change the A¢register to 55. ';,,20' will change Y to 20.¢¢ Goto G[S] [adr] [*brkpt] [C by] [r by] [Pf bit]¢Run program at adr, or PC if not entered. At any time during execution, the¢Break key will return to the monitor and display the current registers and¢PC. Use the 'S' option to run code that ends in an RTS. (Note: When using¢the S option, the PC adr in the register display on return is an internal¢address, not the address where the actual RTS or RTI occurred.)¢¢A breakpoint will create a return point to the monitor whenever a particular¢address or condition is reached. *brkpt will place a 00 (BRK) at the¢breakpoint address. For this reason, breakpoints can not be used for¢programs in ROM. A '?' will be printed in this case. The breakpoint must¢also be set at an opcode rather than an operand location so that it will¢execute. The rest of the parameters add conditions to the breakpoint.¢¢C + by Counts the number of times the breakpoint is reached. Execution¢continues until the BRK is passed the specified number of times. Breakpoints¢can also test for specific conditions by specifying (r) reg name and (by)¢byte it must contain in order to BRK. Processor flags can also be tested by¢'P' + flag character + (bit) for condition. Use the flag characters as in¢the register display.¢¢The breakpoint will be skipped over until the specific condition is reached.¢When both count and condition options are used, the count will apply to the¢number of times the condition is met. Execution speed will be slightly¢slower than real time in this mode. Actual speed will depend on how often¢the program is interrupted to check conditions.¢¢NOTE: A peculiar bug in the ATARI hardware causes breakpoints to be¢intermittenly skipped over. When the BRK interrupt occurs, the program¢counter+2 is pushed on the stack, but instead of jumping through the¢interrupt vector, the OS will occasionally just return to the program at¢PC+2. This is usually a very rare occurrance, but can happen more often when¢using conditional breakpoints on very small and quick loops, thus BRK¢interrupts are occurring very rapidly. It took many years before I was able¢to really understand what was going on, and be assured that the problem was¢indeed in the computer, and not a bug in the monitor.¢¢ADDITIONAL NOTE: This bug does not occur on the '816 processor! Yeeeehaaa!¢(Thanks John.)¢¢ Go command examples.¢G 2000 = Run program at $2000¢G 4000 *4124 = Run at $4000, and break at $4124¢G *3100 A'Q = Run at current PC and break at 3100 when A register¢ equals ASCII 'Q'¢G *4200 C10 PZ1 = Run at PC and break at 4200 the 16th time the zero¢ flag is set¢¢ Remove Breakpt *¢Brkpts remove themselves, and replace what was there when the BRK is¢executed. However, in case the program stops at other than the brkpt, * will¢remove it. This can occur when the Break key is pressed, conditional or¢count values are not reached, or when the BRK is set in an operand rather¢than an opcode. Setting a new brkpt with the G command will also remove an¢unused BRK.¢¢ Exit to DOS X¢¢ Return to Assembler A¢¢ Fill Memory F adr1 adr2 [by1] [by2 by3...]¢Fill memory with 0 if no data bytes. Otherwise enter 1 byte, or a sequence¢of any number of bytes to fill with.¢¢ Transfer Mem T adr1 adr2 adr3¢Move memory from adr1 through adr2 to adr3. Handles overlapping moves.¢¢ Hunt for chars H adr1 adr2 by1 [by2...][!]¢ Hunt for String H adr1 adr2 'ASCII string [!]¢Hunt memory for ASCII string or string of hex bytes up to length of 60. Use¢'!' for a wild card to match anything. Realize the number entry system will¢let you search for things like "A9 'A", (as in LDA #'A), but not the reverse¢of this. Entering "'A A9" will put the hunt into full ASCII form, and search¢for the literal string that you typed in. The second example can actually be¢entered in the form "! 'A A9", using a wild card to avoid the initial '¢identifier. For one more example, let's say you wanted to search for a JSR¢to a MAE defined label. This can be entered as "20 .LABEL .>LABEL".¢¢ Change wild card % char¢Change the wild card for the Hunt command to 'char'. This is used in case a¢character in the search string is '%' or HEX 25.¢¢ Compare mem K adr1 adr2 adr3¢Compare memory from adr1 to adr2 with memory starting at adr3. Displays all¢addresses with differences.¢¢ DEC to HEX # decimal number [no2...]¢ HEX to DEC $ by1 [by2...]¢Displays hex values of a string of decimal numbers and vice versa.¢¢ Change Output O [filespec]¢Send output to screen and filespec. O by itself returns to just screen¢output. Default drive processing is not done on this command. Full¢filespecs must be entered for disk files. Because of this, other devices do¢not need a ':'. ('O P' is sufficient to send output to printer)¢¢ Re-open Editor IOCB E¢This is useful for returning to the text screen from a graphics mode, or¢80-column display, or to reset the screen after changing RAMTOP. The other¢IOCB's used are: #3 disk reads, #4 disk writes, and #6 external output.¢¢ Query MAE symbol table Q adr¢ (Sorry, I was running out of letters)¢Search the current symbol table for a label that matches the value entered¢for adr. If found, the label will be printed. This is basically the reverse¢procedure for symbol table lookup, and as such will only work well when the¢requested value has only one label associated to it.¢¢ Trace Instr I [adr]¢Traces program an instruction at a time. Automatically traces OS calls¢(including jumps with implied return) as one step. Trace normally works on¢programs in ROM, except 'G' and 'R' options as noted below. After each step,¢the monitor will wait for one of the following keypresses to control the¢tracing mode:¢¢Space - Steps one instruction at a time.¢C - Continuous trace.¢D - Disassemble next instructions. Useful for previewing code that¢ you are about to step through. The program counter will remain¢ at its current location.¢G - Execute all instructions up to current 'D' command listing. Use¢ to quickly execute loops or other structures. First use 'D' to¢ find a spot past the structure, then 'G' will execute everything¢ up to that point. This command puts a Breakpoint at the end¢ position, and therefore cannot be used if the program is in ROM.¢S - Execute entire subroutine as one step.¢R - Return from subroutine. Use this command if you are already in a¢ subroutine, and wish to return to the previous level. A BRK will¢ be placed at the instruction the subroutine returns to, and¢ therefore cannot be used for programs in ROM.¢P - Peek the value of the operand of the current instruction.¢Q - Perform a Q monitor command on the operand of the current instruction.¢ If the operand value is defined in the current MAE symbol table, the¢ label name will be printed. You can use this on JMP, JSR and branch¢ intructions to get an idea where you're going, and also on any memory¢ references that have you thinking, "What the heck is *that*?"¢U - Execute the user function.¢X - Ignore instruction. Skip to the next one without executing.¢ESC, RETURN, or BREAK exits trace mode.¢¢ Change Default Drv / 1-8¢All default drive accesses change to drive number entered, including uses in¢the assembler section. The starting default drive number will be the same as¢the current SpartaDOS drive.¢¢ Binary Load L [@adr][-adr] filename¢Load DOS II binary file where it was saved, or at @adr if entered. Prints a¢'?' if the file is not DOS II format. Loads appended files, but @adr only¢works on 1st part. -adr loads raw data with no header using a straight CIO¢transfer. Both PC and default address are set to the load address.¢¢ Binary Save S [-]adr1 adr2 [@adr3] [+]file¢Save DOS II binary file from adr1 to adr2. If @adr3 is entered, it will be¢used as the header allowing the file to load in at a different address than¢where it was saved. Use '-' for a CIO save without header. If + is entered,¢append to existing file.¢¢ Directory V [name or spec] (Sorry, I *am* out of letters)¢Displays disk directory. Default of Dn:*.*. A filespec of D2: = D2:*.*¢¢ Sector Read R adr sector# [ending sector]¢ Sector Write W adr sector# [ending sector]¢Direct sector I/O to default drive. Reads single and double density disks¢automatically including single density sectors 1-3 of a DD disk.¢¢ Hex Arithmetic ? by1(+-*/&!)[by2..] (no spaces)¢Prints hex and decimal values of expression evaluated left to right.¢Can also be used for ASCII convert. (?'A)¢¢ User Function U [adr1] [adr2] [adr3]¢Accepts up to 3 parameters, which will be stored at $F0, $F2, and $F4. $F2¢and $F4 will be 0 if not entered, while $F0 will have the current address if¢not entered. In addition, the carry flag will be set if no parms. Then¢jumps to the end address of the monitor-3. ($BBFD in top of RAM version)¢User function expects an RTS return.¢
