Path: utzoo!utgpu!news-server.csri.toronto.edu!torsqnt!tmsoft!masnet!canremote!john.russell
From: john.russell@canremote.uucp (JOHN RUSSELL)
Newsgroups: comp.lang.c
Subject: IsUnsigned function?
Message-ID: <15303b1aa0bf26a8c5d4@canremote.uucp>
Date: 21 Jul 90 19:15:00 GMT
Organization: Canada Remote Systems Limited, Mississauga, ON, Canada
Lines: 18

None of the answers so fa{ has addressed the question of "space 
efficient".  Any solution that uses "if" stands a chance of generating 
branch instructions.  Any solution that explicitly returns 0 or 1 will 
generate a "clear" instruction, and maybe a "move" instruction with a 16
or 32-bit operand.

The question might also have been checking for knowledge of a particular
chip instruction set, eg. on 68K a moveq.l #1 instruction allows you to 
explicitly return a 1 without wasting 32 bits to hold the operand. 
 
I won't post my solution  (after all, Microsoft is presumably still
asking this question), but is compiles to 3 instructions plus function
linking stuff; one of the instructions has a 16-bit operand, the others
are register-to-register.  (This is on a 68K without any optimization.)
 
John
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