Re: [PATCH v3 next 02/17] tools/nolibc: Optimise and common up the number to ascii functions

[Thomas Weißschuh]

On 2026-02-23 10:17:20+0000, david.laight.linux@xxxxxxxxx wrote:
> From: David Laight <david.laight.linux@xxxxxxxxx>
> 
> Implement u[64]to[ah]_r() using a common function that uses multiply
> by reciprocal to generate the least significant digit first and then
> reverses the string.
> 
> On 32bit this is five multiplies (with 64bit product) for each output
> digit. I think the old utoa_r() always did 36 multiplies and a lot
> of subtracts - so this is likely faster even for 32bit values.
> Definitely better for 64bit values (especially small ones).
> 
> Clearly shifts are faster for base 16, but reversing the output buffer
> makes a big difference.
> 
> Sharing the code reduces the footprint (unless gcc decides to constant
> fold the functions).
> Definitely helps vfprintf() where the constants get loaded and a single
> call is done.
> Also makes it cheap to add octal support to vfprintf for completeness.
> 
> Signed-off-by: David Laight <david.laight.linux@xxxxxxxxx>

Applied, thanks.

Some changes I did:
* Do not use int128 for sparc on clang, as it will also use __multi3.
* Apply Willy's Ack from v1.

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