Freescale Semiconductor MC68881 - Arithmetic Calculation Times - - Dyadic Operations

8
Table 8-14. Arithmetic Calculation Times -- Dyadic Operations
FADD Calculation Time:
ce
+
Normalized
Normalized
+
Zero
+
Infinity
+
NAN
+
ADD 2+ 6 NAN2
Zero + 6 26
2 + 6 NAN2
- 26 6
Infinity + 6 20
6 6 NAN2
- 20 6
+
NAN NAN1 NAN2 NAN2 NAN3
ADD: 24 + if the source and estination exponents are equal, and the source mantissa
is less than the destination mantissa.
26 + if the source and destination exponents are equal, and the source mantissa
is greater than or equal to the destination mantissa.
28+ if the source and destination exponents are not equal.
FCMP Calculation Time:
Source
Destination
+
Normalized
+
Zero
+
Infinity
Normalized
+
CMP 6
6 CMP
8 6
6 8
Zero
+
Infinity
+
8 6
6 8
8 6
6 8
NAN
+
NAN4
NAN4
6 6 6 NAN4
+
NAN NAN1 NAN2 NAN2 NAN3
:MP: 8 if thesource exponent is greater than the desination exponent.
10 if the source exponent is less than or equal to the destination exponent.
FDIV Calculation Time:
Source
Destination
+
Normalized
+
Zero
+
Infinity
+
NAN
DIV: 78 +
80 +
Normalized
+
DIV
Zero
-F
20
NAN
+
Infinity
- -F -
6
8
8 6
6 8
20
NAN2
NAN2
6 8 20 NAN2
6 8 6 8 NAN2
NAN 1 NAN2 NAN3
if the ntermediate result is normalized.
if the
intermediate result is denormalized.
FREESCALE
8-30
MC68881/MC68882 USER'S MANUAL