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A benchmark of three different floating point packages for the 6809

(boston.conman.org)
23 points ingve | 2 comments | 14 Oct 24 09:25 UTC | HN request time: 0.398s | source
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mannyv ◴[18 Oct 24 02:16 UTC] No.41875816[source]▶
If you can find a copy Apple's SANE for the 6502 test it. It was faster than hardware fpus. That was according to a friend who was an FP geek back when.
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1. spc476 ◴[18 Oct 24 03:54 UTC] No.41876206[source]▶
First off, the assembler is for a Motorola 6809, which is not a 6502. Second, one benchmark result I found [1] showed it being a bit slower than some alternatives.

[1] https://www.callapple.org/programming/sane-programming-on-th...

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2. adrian_b ◴[18 Oct 24 08:23 UTC] No.41877377[source]▶
Motorola MC6809 was much faster for floating-point computations than any other 8-bit microprocessor, because it not only had 16-bit additions, but it also had 8 bit by 8 bit multiplications. No other 8-bit microprocessor had multiplication instructions.

MC6809 had a very beautiful ISA in comparison with all other 8-bit microprocessors, but it was launched too late, in 1979, when there already were the 16-bit microprocessors Intel 8086 and Motorola MC68000.

Motorola had made the mistake of developing simultaneously two incompatible instruction sets, MC6809 intended for cheap CPUs and MC68000 intended for expensive CPUs. They should have developed a single architecture, with a stripped-down version of MC68000 for cheap CPUs, like they have done later with MC68008, but only when it was too late, because the cheap version of Intel 8086, i.e. Intel 8088 had already won the IBM PC.