Nintendo Ultra64 Programmer's Manual page 66

Vector Unit Instructions
66
vmadm res_int, s_int, t_frac
vmadn res_frac, dev_null, dev_null[0]
IxI:
#
# single precision integer multiply:
# I * I = I
#
vmudh res_int, s_int, t_int
IxF:
#
# single precision multiply:
# I * F = IF
#
vmudm res_int, s_int, t_frac
vmadn res_frac, dev_null, dev_null[0]
Other combinations are left as an exercise to the reader.