Sign-Extended Register and Immediate from of AND/OR/XORLast reviewed: January 23, 1995Article ID: Q31598 |
The information in this article applies to:
SUMMARYThe Microsoft Macro Assembler will generate sign-extended encodings whenever possible. The following are MASM instructions that will produce sign-extended encodings:
Assembler Sign-Extended Nonsign-Extended Instructions Encodings Encodings AND bx, 0ffffh 83 E3 FF 81 E3 FFFF ADD bx, 0001h 83 C3 01 81 C3 0001 ADC bx, 0fh 83 D3 0F 81 D3 000F OR bx, 1 83 CB 01 81 CB 0001 SBB bx, 0ffffh 83 DB FF 81 DB FFFF SUB bx, 3 83 EB 03 81 EB 0003 XOR bx, 0002h 83 F3 02 81 F3 0002 CMP bx, 0fff2h 83 FB F2 81 FB FFF2 MORE INFORMATIONMASM will choose the sign-extended version of the instruction because of the 1-byte savings in the encoding. The 8088/8086/80186/80286 processors do support the sign-extended encoding, but documentation on this feature is limited. The support of sign-extended encoding is documented in the "8086/8088/80186/80188 Programmer's Pocket Reference Guide" on Page 43.
|
Additional reference words: kbinf 5.00 5.10 6.00
© 1998 Microsoft Corporation. All rights reserved. Terms of Use. |