Re: [coreboot] [PATCH] Seabios on Virtutech Simics x86-440bx model

[Kevin O'Connor]

Hi Magnus,

Is:

for (i = 0, actual_cpu_count = 0; i < MaxCountCPUs; i++) {
        int log_cpus = (ebx >> 16) & 0xff;
        log_cpus = 1UL << fls(log_cpus - 1); /* round up to power of 2 */
        if ((cpuid_features & (1 << 28)) && (i & (log_cpus - 1)) != 0)
            continue;

equivalent to:

int log_cpus = 1;
    if (cpuid_features & (1 << 28)) {
        log_cpus = (ebx >> 16) & 0xff;
        log_cpus = 1UL << fls(log_cpus - 1); /* round up to power of 2 */
    }
    for (i = 0, actual_cpu_count = 0; i < MaxCountCPUs; i+=log_cpus) {

-Kevin

[PATCH] Seabios on Virtutech Simics x86-440bx model

[Magnus Christensson]

Kevin O'Connor wrote:
> Hi Magnus,
>
> Is:
> for (i = 0, actual_cpu_count = 0; i < MaxCountCPUs; i++) {
>     int log_cpus = (ebx >> 16) & 0xff;
>     log_cpus = 1UL << fls(log_cpus - 1); /* round up to power of 2 */
>     if ((cpuid_features & (1 << 28)) && (i & (log_cpus - 1)) != 0)
>         continue;
>
> equivalent to:
> int log_cpus = 1;
> if (cpuid_features & (1 << 28)) {
>     log_cpus = (ebx >> 16) & 0xff;
>     log_cpus = 1UL << fls(log_cpus - 1); /* round up to power of 2 */
> }
> for (i = 0, actual_cpu_count = 0; i < MaxCountCPUs; i+=log_cpus) {

Yes, that should do the same thing.

M.