P8X32A Propeller Datasheet v1.4.0 - MULtiply instructions?

John A. Zoidberg

From the datasheet dated 14/6/2011 - there are grayed out MULtiply instructions in the instruction set list, and it means that it is implemented in the future. I'm curious that is it for the FPGA variant or are these present in future batches of Prop 1?

I'm certain that back in 2011 the Verilog code for the Prop 1 does not exist yet for open-source. So I believe that it could be for the future batches of P1.

But, it's 2014 now and is there any news about these instructions? I've been longing for a Prop with at least a multiply instruction inside.

Heater.

I'm very sure there is no multiply anywhere in the current P1. It's just one of those things that never happened, like the mythical port B. It's almost certain that if there were a multiply in the design pipeline it would have shown up in the open source Verilog code for the P1.

ozpropdev

The multiply opcode was allocated but never implemented. The PropTool recognizes MUL,MULS,ENC,ONES and generates the
correct opcodes though. In the Verilog P1 MUL/MULS have been implemented and also are being used for other experimental instructions.

Mark_T

ozpropdev wrote: »

The multiply opcode was allocated but never implemented. The PropTool recognizes MUL,MULS,ENC,ONES and generates the
correct opcodes though. In the Verilog P1 MUL/MULS have been implemented and also are being used for other experimental instructions.

Just had a thought - rather than being cog instructions perhaps the multiplier could have been
invisaged as a pipelined unit in the hub, with a 2-clock overhead and 16-clock latency - then each
cog could issue a multiply when its hub slot comes by and collect the result next time....