Translate nasm code to Tasm

[os_ambition]

Hi,
Please help me to translate this to TASM code

and   di, byte -0x20


thank u very much in advance.

os_ambition

[Pype.Clicker]

why in the world do you need to use TASM ??
I thought that assembler was obsolete for years ...

btw, if you *really* need it that hard, simply remove the "byte" information (TASM should be able to guess that you'll be happy with a one-byte constant automatically) ...

[os_ambition]

what do you mean by -0x20, is this negative 20 hex? I need this value in tasm.


thank u again

[Candy]

what do you mean by -0x20, is this negative 20 hex? I need this value in tasm.


thank u again

that should be the 2-s complement of 0x20, or (as a byte) 0xE0.

[astrocrep]

just try

Code: Select all

and   di, -20h  

if that doesn't work then try:

Code: Select all

mov   ax, -20h
and   di, ax  

[Pype.Clicker]

that should be the 2-s complement of 0x20, or (as a byte) 0xE0.

Hey, beware...
the byte thing means the argument should be encoded as a byte, but it will be expanded to a word ... now, iirc that expansion is signed.

In other word, we're using (cf p 3-31 of instruction set reference -- 24547107.pdf)

opcode:"83 /4 ib" instruction:"AND r/m16, imm8" description:"r/m16 AND imm8 (sign-extended)"

That means that the equivalent in TASM is

Code: Select all

AND di, FFE0h

and not

Code: Select all

AND di, E0h

No need to say that the author of the NASM code was an obfuscating person (using 2's complement with bit-by-bit logical instructions makes no sense *at all*)

[os_ambition]

thank u very very much Pype.clicker,

that's why I like TASM, it's simple and straight