ref: 6b26016daffab8f008c3aa40ce4946a942f19bd4
dir: /bin/br/
#!/bin/rc
# SBLC_PWM_CTL2: bytes 15:0, range 0 (off) to v>>16 (full)
if(! ~ $#* 1){
	echo usage: $0 factor
	exit 'usage'
}
v=`{seg -Lr igfxmmio 0x400000 0xc8254}
if(~ $#v 0)
	exit 'no such named segment'
v=`{echo 'v='$v'; v & ~0xffff | ((v>>16) / '$1')' | pc -n}
if(! ~ $#v 1)
	exit 'invalid factor'
seg -Lw igfxmmio 0x400000 0x48254 $v