AMD-K6-2E Datasheet, PDF (46/332 Pages) Advanced Micro Devices – AMD-K6™-2E Embedded Processor

AMD-K6™-2E Processor Data Sheet
Preliminary Information
22529B/0—January 2000
79 78
Sign
The eight floating-point registers are physically 80 bits wide
and labeled FPR0–FPR7. Figure 11 shows the format of these
floating-point registers. See “Floating-Point Register Data
Types” on page 30 for information on allowable floating-point
data types.
Exponent
64 63
0
Significand
Figure 11. Floating-Point Register
The 16-bit FPU status word register contains information about
the state of the floating-point unit. Figure 12 shows the format
of the FPU status word register.
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
BC
3
TOSP
CCC E S PUOZ D I
210SF EEEE EE
Symbol
B
C3
TOSP
C2
C1
C0
ES
SF
PE
UE
OE
ZE
DE
IE
Description
Bits
FPU Busy
15
Condition Code
14
Top of Stack Pointer
13–11
Condition Code
10
Condition Code
9
Condition Code
8
Error Summary Status 7
Stack Fault
6
Exception Flags
Precision Error
5
Underflow Error
4
Overflow Error
3
Zero Divide Error
2
Denormalized Operation Error 1
Invalid Operation Error 0
TOSP Information
000 = FPR0
111 = FPR7
Figure 12. FPU Status Word Register
28
Software Environment
Chapter 3