|
From: | Uros Bizjak |
Subject: | [avr-gcc-list] Re: AVR byte swap optimization |
Date: | Mon, 27 Nov 2006 08:33:36 +0100 |
Denis Vlasenko wrote:
The following macro expands to some rather frightful code on the AVR: #define BSWAP_16(x) \ ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8))Sometimes gcc is generating better code if you cast values instead of masking. Try: ( (uint8_t)((x) >> 8) | ((uint8_t)(x)) << 8 )
gcc > 3.4.x always generates better code for casted values. This is PR middle-end/29749, and it affects i386 linux too. Uros.
[Prev in Thread] | Current Thread | [Next in Thread] |