Comment by cesarb

> [...] on i686 bringing it to 6+BP (not 4+BP) meanwhile x86_64 has 14+BP (not 16+BP).

That is, on i686 you have 7 GPRs without frame pointers, while on x86_64 you have 14 GPRs even with frame pointers.

Copying a comment of mine from an older related discussion (https://news.ycombinator.com/item?id=38632848):

"To emphasize this point: on 64-bit x86 with frame pointers, you have twice as many registers as on 32-bit x86 without frame pointers, and these registers are twice as wide. A 64-bit value (more common than you'd expect even when pointers are 32 bits) takes two registers on 32-bit x86, but only a single register on 64-bit x86."