[comp.lang.c] wide arguments and/or argument wide

shirono@hcx3.SSD.HARRIS.COM (12/06/88)

In comp.lang.c, gl8f@bessel.acc.Virginia.EDU writes:
> Why are arguments to C functions always widened to ints or doubles?

PDP 11.

> This
> makes sense when the argument is being widened to the buswidth (which
> ints are supposed to be), but doubles are often larger than that.

The reason for auto-type-conversion to double was because the FPP on the
PDP 11 could operate in one of two modes: single and double precision, but
going from one to the other was rather costly.  This (I believe) was the
reason why DMR specified that all floating point arithmetic was to be
performed in double: have the program startup routine set the FPP to double
mode and just keep going.

--Roberto
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