JitArm64: Optimize divwux

When the divisor is a constant value, we can emit more efficient code.
For powers of two, we can use bit shifts. For other values, we can
instead use a multiplication by magic constant method.

- Example 1 - Division by 16 (power of two)
Before:
mov    w24, #0x10                ; =16
udiv   w27, w25, w24

After:
lsr    w27, w25, #4

- Example 2 - Division by 10 (fast)
Before:
mov    w25, #0xa                 ; =10
udiv   w27, w26, w25

After:
mov    w27, #0xcccd              ; =52429
movk   w27, #0xcccc, lsl #16
umull  x27, w26, w27
lsr    x27, x27, #35

- Example 3 - Division by 127 (slow)
Before:
mov    w26, #0x7f                ; =127
udiv   w27, w27, w26

After:
mov    w26, #0x408               ; =1032
movk   w26, #0x8102, lsl #16
umaddl x27, w27, w26, x26
lsr    x27, x27, #38

0 files changed, 0 insertions, 0 deletions