MAX - RISC-V instruction reference

maxMaximum (signed) 
Sets t1 to the larger of t2 and t3, comparing as signed.
RISC-V manual: max 
Forms  max , ,   
Operands t1 Any integer register, x0 to x31, or its named alias, such as zero, t0 or t6. 
t2 An integer register. It may be the same register as t1. 
t3 An integer register. It may be the same register as t1. 
Branch free, unlike the usual blt and move
 .text
li t0, 18
li t1, 5
# t0=18, t1=5; max writes 18 to t2.
max t2, t0, t1