steves@ncr-sd.SanDiego.NCR.COM (Steve Schlesinger) (07/01/88)
I tried email this directly but it bounced. Sorry (to the original poster) for the delay in answering. Sorry to everyone else if it was aleady answered and I missed it. In article <20039@beta.UUCP> you write: >To some extent, the lack of detailed knowledge >of C is my reason for not using it. (For example: why is 'a+=b' faster >than 'a=a+b'? Seems to me that the two are identical and should generate >the exact same code.) When optimized, yes they are the same. Without optimization consider a[i][j] = a[i][j] + b vs. a[i][j] += b In the second case the address a[i][j] is computed only once and reused. This is faster both at compilation and execution times. An optimizer would convert the first to the second. --
smryan@garth.UUCP (Steven Ryan) (07/02/88)
>In the second case the address a[i][j] is computed only once and reused. >This is faster both at compilation and execution times. > >An optimizer would convert the first to the second. Assuming none are *volatile*.