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Old 28 October 2018, 19:10   #581
plasmab's Avatar
Join Date: Sep 2016
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Originally Posted by grond View Post
Well, ldm, stm, mul and divs all do well with microcode. Not much but not nothing either. Thanks God or rather Sophie Wilson that they did use microcode and not insist on the programmer using a bunch of primitive instructions to implement these instructions in macrocode...

I think MIPS and also the earlier SPARC required the programmer to use a sequence of shift-add/subtract instructions in order to make multiplications and divisions.

IIRC Sophie had a bit of a sulk (overstating for effect) about DIVS being in there at all. It wasn’t there on ARMv1. She was also pretty against the FPA ... I have one of those too in my A540 [emoji4]

[ Show youtube player ]

See from around 7 mins in. Notice that ARM is referred to as the Acorn RISC Machine.

Sophie always seemed pathologically against having anything complex in the chip. Rightly or wrongly

Last edited by plasmab; 28 October 2018 at 19:29.
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