def execute_mulhu( s, inst ): a, b = s.rf[inst.rs1], s.rf[inst.rs2] multhi = multhi64( a, b ) s.rf[ inst.rd ] = sext_xlen( multhi ) s.pc += 4
def execute_mulhsu( s, inst ):
a, b = s.rf[inst.rs1], s.rf[inst.rs2]
a_s = signed(a, 64)
a = abs(a_s)
multlo = trim_64( a * b )
multhi = multhi64( a, b )
# negate -- taken from
# http://stackoverflow.com/questions/1541426/computing-high-64-bits-of-a-64x64-int-product-in-c
# this requires us to do low multiplication as well, so it's probably
# not very efficient
if a_s < 0:
multhi = ~multhi
if multlo == 0:
multhi += 1
s.rf[ inst.rd ] = sext_xlen( multhi )
s.pc += 4