Table of Contents
Advertisement
HP E2444A
80386DX/DXL Preprocessor Interface
Table 2-2. Status Field Encoding
80386
Cycle Type
Interrupt Acknowledge
I/O Read
I/O Write
Opcode Fetch
Halt/Shutdown
Memory Read
Memory Write
Valid Bytes in Transfer
(from BE0# through BE3# )
Double Word (all bytes valid)
Higher 3 Bytes
High Word
Byte 3
Lower 3 Bytes
Middle Word
Byte 2
Low Word
Byte 1
Byte 0
Size of Transfer
16-bit Transfer
32-bit Transfer
Note: X = don't care. The actual status field is a 15-bit field; however, bits 11 through
14 are not shown since they are "don't cares."
Status Bit
10 9 8 7 6 5 4 3 2 1 0
x x x x x x x x 0 0 0
x x x x x x x x 0 1 0
x x x x x x x x 0 1 1
x x x x x x x x 1 0 0
x x x x x x x x 1 0 1
x x x x x x x x 1 1 0
x x x x x x x x 1 1 1
x x x 0 0 0 0 x x x x
x x x 0 0 0 1 x x x x
x x x 0 0 1 1 x x x x
x x x 0 1 1 1 x x x x
x x x 1 0 0 0 x x x x
x x x 1 0 0 1 x x x x
x x x 1 0 1 1 x x x x
x x x 1 1 0 0 x x x x
x x x 1 1 0 1 x x x x
x x x 1 1 1 0 x x x x
x x 0 x x x x x x x x
x x 1 x x x x x x x x
Analyzing the Intel 80386DX/DXL
2-7
Advertisement
Table of Contents
