Computational Units
2 – 35
2
If the upper half of the input contains all sign bits, the SE register value is
determined by the second derive exponent operation as shown below.
1. Detect Exponent, Modifier = HI
First Input: 11111111 11111111 (Must be upper half)
SE set to: -15
2. Detect Exponent, Modifier = LO
Second Input: 11110110 11010100
SE now set to: -19
3. Normalize, Modifier=HI, No [SR OR], SE = –19 (negated)
First Input: 11111111 11111111
SR: 00000000 00000000 00000000 00000000
All values of SE less than –15 (resulting in a shift of +16 or more) upshift
the input completely off scale.
4. Normalize, Modifier=LO, [SR OR], SE = –19 (negated)
Second Input: 11110110 11010100
SR: 10110110 10100
000 00000000 00000000