Intel 80287 - Page 245

THE 80286 INSTRUCTION SET
CWO-Convert Word to Doubleword
Opcode
Instruction
Clocks Description
99
CWD
2
Convert word to daubleword (DX:AX = AX)
FLAGS MODIFIED
None
FLAGS UNDEFINED
None
OPERATION
CWDconverts the signed word in AX to a signed doubleword in DX:AX. It does so by extending the
top bit of AX into all the bits of DX.
PROTECTED MODE EXCEPTIONS
None
REAL ADDRESS MODE EXCEPTIONS
None
8-35
pcjs.org