Breakpoints are added using the Disassembly window. A user selects an instruction line from the listing and presses the 'S' (Set) key. The breakpoint can be removed by pressing the 'R' (Remove) key. When the breakpoint is set the address in the listing is highlighted by turning red.
When a breakpoint is created the opcode at the address is saved and replaced by a "HALT" ($15) instruction. When the CPU encounters this code VCC is paused and the original opcode is restored. When the CPU is started the HALT instruction is placed back into memory after executing the original instruction.
Breakpoints are added using the Disassembly window. A user selects an instruction line from the listing and presses the 'S' (Set) key. The breakpoint can be removed by pressing the 'R' (Remove) key. When the breakpoint is set the address in the listing is highlighted by turning red.
When a breakpoint is created the opcode at the address is saved and replaced by a "HALT" ($15) instruction. When the CPU encounters this code VCC is paused and the original opcode is restored. When the CPU is started the HALT instruction is placed back into memory after executing the original instruction.