Module 4 learning unit 11:
Data Types
�Internally, all data operands are converted to the 80-bit temporary real format. We have 3 types.
•Integer data type
•Packed BCD data type
•Real data type
Coprocessor data types Integer Data Type
Packed BCD
Real data type
Example
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Converting a decimal number into a Floating-point number.
1) Converting the decimal number into binary form.
2) Normalize the binary number
3) Calculate the biased exponent.
4) Store the number in the floating-point format.
Example
Step Result
1) 100.25
2) 1100100.01 = 1.10010001 * 26
3) 110+01111111=10000101
4 ) Sign = 0
Exponent =10000101
Significand = 10010001000000000000000
•In step 3 the biased exponent is the exponent a 26 or 110,plus a bias of 01111111(7FH)
,single precision no use 7F and double precision no use 3FFFH.
•IN step 4 the information found in prior step is combined to form the floating point no.
INSTRUCTION SET
�The 8087 instruction mnemonics begins with the letter F which stands for Floating point and distinguishes from 8086.
�These are grouped into Four functional groups.
�The 8087 detects an error condition usually called an exception when it executing an
instruction it will set the bit in its Status register.
Types
I. DATA TRANSFER INSTRUCTIONS.
II. ARITHMETIC INSTRUCTIONS.
III. COMPARE INSTRUCTIONS.
IV. TRANSCENDENTAL INSTRUCTIONS.
(Trigonometric and Exponential)
Data Transfers InstructionsREAL TRANSFER FLD Load real
