Syntax:
BC list
BC *
Description:
Permanently removes one or more breakpoints by number, or all breakpoints if the wildcard (*) is used.
Example:
To remove breakpoints one and two, type:
BC 1 2
Syntax:
BD list
BD *
Description:
Temporarily disables one or more breakpoints by number, or all breakpoints if the wildcard (*) is used.
Example:
To temporarily disable breakpoints one and two, type:
BD 1 2
Syntax:
BE list
BE *
Description:
Enables one or more breakpoints which had previously been disabled with the Breakpoint Disable (BD) command.
Examples:
To enable breakpoints one and two, type:
BE 1 2
To enable all breakpoints, type:
BE *
Syntax:
BP
BP address
BP addressLlength
Description:
Sets a breakpoint on the given address or range of addresses. If the breakpoint is on a memory location, it will be triggered if the instruction at that location is about to be executed, or if the memory location is read or written to. If the breakpoint is on an I/O port, it will be triggered if the port is accessed.
After setting a breakpoint, use the Go (G) command to start running the emulator in stepping mode. Breakpoint functionality is available only in stepping mode, not in normal running mode.
Examples:
To set a breakpoint at the current execution address (the address contained in the PC register) type:
BP
To set a breakpoint at address $BF00, the ProDOS Machine Language Interface, type:
BP BF00
To set a breakpoint on I/O ports $C0E0-$C0EF, trapping all disk I/O on slot 6, type:
BP C0E0L10
Syntax:
BW
Description:
Changes the debugger screen to black and white mode.
Syntax:
COL
Description:
Changes the debugger screen to color mode.
Syntax:
G
G address
Description:
Starts running the emulator in stepping mode. Stepping mode is slower than the normal running mode, but it allows execution to be interrupted by a triggered breakpoint, the escape key, or execution reaching the address given in the Go command.
Example:
To continue execution until the program counter reaches $C27D, the address of WAITKEY1, type:
G C27D
Syntax:
I address
Description:
Simulates reading the specified I/O port.
Example:
To simulate a read of port $C083, switching the banked memory at $D000 from ROM to RAM, type:
I C083
Syntax:
KEY value
Description:
Simulates pressing a key. The given value is passed to the next program that reads the keyboard data port at $C00X.
Example:
To simulate pressing the Return key, type:
KEY 8D
Syntax:
MD address
Description:
Displays the contents of memory starting at the specified address, in hexadecimal notation.
Example:
To display memory at $BF00, type:
MD BF00
Syntax:
MDC address
Description:
Displays disassembled code starting at the specified address.
Example:
To display code starting at $F832, type:
MDC F832
Syntax:
ME address value(s)
Description:
Writes the given values to memory locations starting at the specified address.
Example:
To write $A9 to memory location $FBE4 and $0A to memory location $FBE5, type:
ME FBE4 A9 0A
Syntax:
MF addressLlength value
Description:
Fills a range of memory locations with the given value.
Example:
To fill memory locations $FBE4 through $FBEE with the value $EA, type:
MF FBE4L0B EA
Syntax:
O address value
Description:
Writes the specified value to the given I/O port. If value is not specified, a value of zero is assumed.
Example:
To write $FF to I/O port $C070, type:
O C070 FF
Syntax:
R register=value
where register is:
A Accumulator X X index Y Y index PC Program counter SP Stack pointer
Description:
Sets the specified register in the emulated CPU to the given value. The value is adjusted if necessary to fit the valid range of values for the specified register.
Examples:
To set the value in the accumulator to $80, type:
R A=80
To set the program counter to $FA62, type:
R PC=FA62
Syntax:
Rf
where f is:
N Sign flag V Overflow flag R Reserved flag B Break flag D Decimal flag I Interrupt flag Z Zero flag C Carry flag
Description:
Clears the specified processor status flag.
Example:
To clear the carry flag, type:
RC
Syntax:
Sf
where f is:
N Sign flag V Overflow flag R Reserved flag B Break flag D Decimal flag I Interrupt flag Z Zero flag C Carry flag
Description:
Sets the specified processor status flag.
Example:
To set the decimal flag, type:
SD
Syntax:
T
T count
Description:
Executes one or more instructions at the current program counter (PC) location.
Example:
To execute five assembly language instructions, type:
T 5
Syntax:
ZAP
Description:
Removes the current instruction (the instruction to which PC points) by replacing it with one or more NOP instructions.