From ph Fri Oct 22 18:25:55 1982
To: ikonas
Subject: math subroutines

See /usr/ph/ik/math/alu.k for tips on how to do basic arithmetic.
For optimization freaks, see the "tricks" section at the end of that file.

Also, I have a few subroutines which might be useful to the rest of you:
   /usr/ph/ik/math/mul32.k    multiplies two 32-bit operands, yeilding 64 bits
   /usr/ph/ik/math/div32.k    divides 32-bit operands, yeilds quotient & rem.
   /usr/ph/ik/math/div64.k    divide 64-bit num. by 32-bit denom.
   /usr/ph/ik/math/sqrt.g     square root of a 32-bit integer (11.7 us!)

There are comments at the beginning of these programs which tell you
how to set up the registers before calling.

From ph Wed Nov  3 06:49:17 1982
To: ikonas
Subject: random news

1. I have several new subroutines in /usr/ph/ik/math:
	sqrt64:	64-bit square root (34 us average)
	mult32:	32-bit multiply using TRW multiplier (20 instructions)
	bilin:	bilinear interpolation (15 or 18 instructions)

From ph Thu Aug 11 03:18:17 1983
To: ikonas
Subject: floating point routines for Ikonas

I've written BPS microcode subroutines for floating point arithmetic.
They're called fadd, fsub, fmul, fdiv, int_flt, flt_int, and fcmp.
Look at the source file, /usr/ph/ik/math/farith.k, for the calling
conventions, or talk to me.  They're roughly twice as fast as the
ones advertised by Biographics in Dallas, 1/6 to 1/2 as fast as a VAX
with floating point accelerator (depending on how you measure it).

				  IKONAS	  VAX 780
A table of speeds [usec]:  Biographics  mine    float   double
					     (from assembler, not C)
		add/subtract	15	 8	1.3	2.4
		multiply	20	 8	1.7	4.3
		divide		22	11	4.9	9.2

If there's demand, I can write floating point sqrt, log, exp, and
trig functions too.