Re: [U-Boot] [RFC PATCH] Pre-console buffer for ARM

Dear Graeme Russ,

In message CALButC+t=OUL9XgQnfyAdZmgPJRp7mdRwEE9LKogYHEg1D+m4g@mail.gmail.com you wrote:

...

If you want to support arbitrary buffer sizes, then just use

   #define CIRC_BUF_IDX(idx) ((idx) % CONFIG_SYS_TMP_CON_BUF_SZ)

I know, but I was concerned that you wouldn't like the use of modulo arithmetic for every putc() - But I suppose thats cheaper than a compare plus branch...

Well, the difference of "i & (CONFIG_SYS_TMP_CON_BUF_SZ-1)" versus "i % CONFIG_SYS_TMP_CON_BUF_SZ" is 1 versus 4 assembler instructions on Power, and 2 versus 5 assembler instructions on ARM. I think we can tolerate this.

Best regards,

Wolfgang Denk