AMD-K6-2ESLASH233AMZ datasheet(232/332 Pages) AMD

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Floating-Point and Multimedia Execution Units

Chapter 10

AMD-K6™-2E Processor Data Sheet

22529B/0—January 2000

Preliminary Information

IGNNE# is used by the external hardware to control the effect

of an unmasked floating-point exception. Under certain

circumstances, if IGNNE# is sampled asserted, the processor

ignores the floating-point exception.

Figure 80 illustrates an implementation of external logic for

supporting floating-point exceptions. The following example

explains the operation of the external logic in Figure 80:

1. As the result of a floating-point exception, the processor

asserts FERR#.

2. The assertion of FERR# and the sampling of IGNNE#

negated indicates the processor has stopped instruction

execution and is waiting for an interrupt.

3. The assertion of FERR# leads to the assertion of INTR by

the interrupt controller.

4. The processor acknowledges the interrupt and jumps to the

corresponding interrupt service routine in which an I/O

write cycle to address port F0h leads to the assertion of

IGNNE#.

5. When IGNNE# is sampled asserted, the processor ignores

the floating-point exception and continues instruction

execution.

6. When the processor negates FERR#, the external logic

negates IGNNE#.

See “FERR# (Floating-Point Error)” on page 103 and “IGNNE#

(Ignore Numeric Exception)” on page 108 for more details.

AMD-K6-2E/233AMZ Datasheet(PDF) 232 Page - Advanced Micro Devices