AMD-K6-2E Datasheet, PDF (48/332 Pages) Advanced Micro Devices – AMD-K6™-2E Embedded Processor

AMD-K6™-2E Processor Data Sheet
Preliminary Information
22529B/0—January 2000
Floating-Point
Register Data Types
Floating-point registers use four different types of data —
packed decimal, single-precision real, double-precision real,
and extended-precision real. Figures 15 and 16 show the
formats for these registers.
79 78 72 71
Ignore
S _or
Zero
0
Precision — 18 Digits, 72 Bits Used, 4-Bits/Digit
Description
Bits
Ignored on Load, Zeros on Store 78-72
Sign Bit
79
Figure 15. Packed Decimal Data Register
Single-Precision Real
Double-Precision Real
63 62
52 51
S
Biased
Exponent
S = Sign Bit
Extended-Precision Real
79 78
64 63 62
S
Biased
I
Exponent
S = Sign Bit
I = Integer Bit
Figure 16. Precision Real Data Registers
31 30 23 22
0
S
Biased
Exponent
Significand
S = Sign Bit
0
Significand
0
Significand
30
Software Environment
Chapter 3