Mathematical Assist Instructions 
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 Mathematical Assist Instructions

Can anyone tell me what the Opcode & register configuration is for the
LOG transcendental instruction is. I am unable to get my hands on the
S/370 Mathematical Assist Manual and need to compute LOG from within
an assembler subroutine.

Thanks.



Sat, 30 Jan 1999 03:00:00 GMT  
 Mathematical Assist Instructions

Quote:

>Can anyone tell me what the Opcode & register configuration is for the
>LOG transcendental instruction is. I am unable to get my hands on the
>S/370 Mathematical Assist Manual and need to compute LOG from within
>an assembler subroutine.

B280   LGND  Natrual log (base e) double
B281   LGNE  Natural log (base e) single
B284   LGCD  Common log (base 10) double
B285   LGCE  Common log (base 10) single

I think these only work on the 4381 processor.
The only math assist instructions carried over
to the S/390 are the square root instructions.

These and all of the other S/3x0 op-codes are published
on Tachyon Software's web site at:
http://www.tachyonsoft.com/tachyon/instmain.html

Hope this helps.
David Bond - Tachyon Software



Sat, 30 Jan 1999 03:00:00 GMT  
 Mathematical Assist Instructions

Quote:

> Can anyone tell me what the Opcode & register configuration is for the
> LOG transcendental instruction is. I am unable to get my hands on the
> S/370 Mathematical Assist Manual and need to compute LOG from within
> an assembler subroutine.

> Thanks.

The Mathmatical assist functions are all RRE format and
the operands are floating point registers.

Common Log

For long operands use  x'B28400(r1)(r2)'
For short operands use x'B28500(r1)(r2)

Natural Log

For long  operands x'B28000(r1)(r2)'
For short operands x'B28100(r1)(r2)'

--
Steve Sinclair
Advanced Systems Engineer
Application Implementation and Support
EDS (New Zealand) Ltd



Tue, 02 Feb 1999 03:00:00 GMT  
 Mathematical Assist Instructions

Quote:

> Can anyone tell me what the Opcode & register configuration is for the
> LOG transcendental instruction is. I am unable to get my hands on the
> S/370 Mathematical Assist Manual and need to compute LOG from within
> an assembler subroutine.

> Thanks.

The Mathmatical assist functions are all RRE format and
the operands are floating point registers.

Common Log

For long operands use  x'B28400(r1)(r2)'
For short operands use x'B28500(r1)(r2)

Natural Log

For long  operands x'B28000(r1)(r2)'
For short operands x'B28100(r1)(r2)'

--
Steve Sinclair
Advanced Systems Engineer
Application Implementation and Support
EDS (New Zealand) Ltd



Tue, 02 Feb 1999 03:00:00 GMT  
 
 [ 4 post ] 

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