9- 24 M68040 USER’S MANUAL MOTOROLA
DENORMALIZED SINGLE PRECISION
31 30 23 22 0
0394062636479809495
$0S
$0 $0 $00
FORMAT IN STATE FRAME
MANTISSAEXPS
FRACTION
DENORMALIZED DOUBLE PRECISION
63 62 52 51 0
0101162636479809495
$0S
$0 $0 $0
0
FORMAT IN STATE FRAME
MANTISSAEXPS
MANTISSA
(a) Single Precision
(b) Double Precision
Figure 9-9. Format of Denormalized Operand in State Frame
9.7 FLOATING-POINT ARITHMETIC EXCEPTIONS
The following eight user floating-point arithmetic exceptions are listed in order of priority.
The MC68040 generates the first seven exceptions in hardware and the eighth only in
software.
• Branch/Set on Unordered (BSUN)
• Signaling Not-A-Number (SNAN)
• Operand Error (OPERR)
• Overflow (OVFL)
• Underflow (UNFL)
• Divide by Zero (DZ)
• Inexact 2 (INEX2)
• Inexact 1 (INEX1)
INEX1 exception is the condition that exists when a packed decimal operand cannot be
converted exactly to the extended-precision format in the current rounding mode. Since
