ESC Escape Flags: not altered
ESC coprocessor's-opcode,source
ESC is used to pass control from the microprocessor to a coprocessor,
such as an 8087 or 80287. In response to ESC, the microprocessor
accesses a memory operand--the instruction for the coprocessor--and
places it on the bus. The coprocessor watches for ESC commands and
executes the instruction placed on the bus, using the effective
address of source.
--------------------------------------------------------------------------
Operands Clocks Transfers Bytes Example
byte(word)
immediate, memory 8(12) + EA 1 2-4 ESC 6,ADR[SI]
immediate, register 2 - 2 ESC COPROC-CODE,AH
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Notes: In order to synchronize with the math coprocessor,
the programmer must explicitly code the WAIT
instruction preceding all ESC instructions. The
80286 and 80386 have automatic instruction
synchronization, hence WAITs are not needed.
Seealso:
This page last updated on Fri Nov 30 10:49:50 MSK 2001
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