csrrw
Atomic read/write CSR
Reads the CSR into t0 and writes t1 into it, as one atomic step.
Forms
csrrw , ,
Operands
t0- Any integer register,
x0tox31, or its named alias, such aszero,t0ort6. csr- A control and status register, written by name or number, such as
fcsr,fflags,frm,cycle,time,instret,ustatus,uepc,ucauseorutval. See the supported registers. t1- An integer register. It may be the same register as
t0.
# Initialize fcsr=0; csrrw returns old fcsr in t0 and leaves fcsr=1.
.text
li t3, 0
csrw t3, fcsr
li t1, 1
csrrw t0, fcsr, t1