Performance of the 8088 on PC, PCjr and Tandy 1000

It’s well-known that you should measure the performance of your code, and not rely only on the opcode’s “cycle counts”.

But how fast is an IBM PC 5150 compared to a PCjr ? or to a Tandy 1000? or how fast is the Tandy 1000 HX in fast mode (7.16Mhz) compared to the slow mode (4.77Mhz) ? Or how fast is a nop compared to a cwd ?

I created a test (perf.asm) that measures the performance of different opcodes and run it on different Intel 8088 machines. I run the test multiple times just to make sure the results were stable enough. All interrupts were disabled, except the Timer (of course). And on the PCjr the NMI is disabled as well.

Without further ado, here are the results:

Continue reading “Performance of the 8088 on PC, PCjr and Tandy 1000”


Tandy 64, and intro for the Tandy 1000 and more

With PVM with released an intro for the Tandy 1000 HX.

The Tandy 1000 HX uses the Intel 8088-2 CPU. Which is a suuuuper slow CPU (slower than the 8086). With all its wait states and its limitations on the video card (no hardware sprites, no charset redefinition) it makes it comparable with a Commodore 64. In fact, for certain things a Commodore 64 if way faster.

Without further ado, this is the Tandy intro:

Source code here:

And we’ve just released another chipdisk, this time with Brazilian music:

Source code:


Long time no see: UniJoystiCle for all platforms

I’ve been busy. I still have no spare time to work on my retro projects, but I have a plan. And it can’t fail. I plan to port the UniJoystiCle + The Uni Games to the following platforms:

  • Commodore VIC 20: UniJoystiCle (single joystick) + The Uni Games
  • Commodore PET: UniJoystiCle in expansion port (single joystick) + The Uni Games
  • Commodore 128: UniJoystiCle (same as the C64) + The Uni Games in VCD mode using the Z80 CPU
  • Tandy 1000: UniJoystiCle + The Uni Games (graphics mode 320×200 16 colors)
  • Commodore 64: Add paddle support to the UniJoystiCle

Continue reading “Long time no see: UniJoystiCle for all platforms”