SLTZ: RISC-V instruction reference

sltzSet less than zero Pseudo-instruction
Sets the first register to 1 if the second is less than zero, otherwise to 0.
RISC-V manual: slt 
Forms  sltz ,   
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. 
 .text
li t0, -1
# t0=-1; sltz writes 1 to t2.
sltz t2, t0