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GDS - An integrated development environment for G80/Z80

GDS includes:

• an editor, to allow program code to be created and edited
• an assembler and a linker, to convert the assembly code to machine code
• a simulator that allows the user to observe the actual operation of her assembly language program.

The simulator illustrates the operation of the microprocessor as it executes the user's program. The user's program may be run continuously, run up to a breakpoint, stepped through one instruction at a time, or stepped through one machine cycle at a time.

• In the single-cycle mode, the movement of data between registers within the microprocessor and external memory is shown.
• In the single-instruction mode, the result of each assembly instruction is shown.
• In the run-mode, the user's program runs continuously.
• A break-point may be set to stop the user's program when it reaches a particular instruction.
• A trace of executed instructions is shown
• A trace of the machine cycles is shown
• A dis-assembly of the machine code is shown

Various input and output devices, such as LEDs, switches, 7-segment displays, counters, timers, hexadecimal keyboard, stepper motor, and a LCD may be incorporated into the user's program. These are also simulated, so allowing the user to observe the operation of realistic systems.

Some of the input/output devices are capable of generating interrupt requests to the microprocessor. The manner by which the microproceesor responds to such an interrupt request may be selected. The response of the microprocessor to these requests may also be observed by single-stepping.

Many example programs are given, each illustrating a programming technique.

The screenshot below shows the operation of a system using a simple output port, a keypad, and a stepper motor. The program writes a binary count to the simple port and, when a number key on the keypad is pressed, this task is interrupted and the stepping motor steps the requested number of times.

For a larger image, with annotations, click here