ST20C2 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST20C2

Instruction Set Reference Manual

STMicroelectronics 

unpacksn

unpacksn

unpack single length fp number

Code: 26 F3

Description: Unpack a packed IEEE single length floating point n umber. Areg

initially holds the packed number, and the instruction returns the exponent in Breg and

the fractional field in Areg, not including the implied most significant bit for normalised

numbers. In addition a code indicating the type of number is added to 4 times the

initial value of Breg and left in Creg. The codes are:

0

if Areg is zero

1

if Areg is a denormalised or normalised number

2

if Areg is an infinity

3

if Areg is not-a-number

Definition:

Areg′ ← fractional field contents of Areg

Breg′ ← exponent field contents of Areg

Creg′ ← 4 × Breg + ‘code’ of type of Areg (see above)

Error signals: none

Comments:

Secondary instruction.

See also: roundsn postnormsn

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