CODEWITHSUNDEEP
assemblynasmx86-64yasm
Matthew Sainsbury
Matthew Sainsbury

Reputation: 1488

yasm: Expected `,' with immediate value

Given the following assembly program:

BITS 64
mov rax, 0b111

Yasm outputs:

error: expected `,'

Why does it expect a comma here? NASM happily assembles this.

Upvotes: 2

Views: 261

Answers (1)

Michael
Michael

Reputation: 58467

From the YASM manual:

3.5.1. Numeric Constants
A numeric constant is simply a number. NASM allows you to specify numbers in a variety of number bases, in a variety of ways: you can suffix H, Q or O, and B for hex, octal, and binary, or you can prefix 0x for hex in the style of C, or you can prefix $ for hex in the style of Borland Pascal.

Some examples:
mov ax,10010011b ; binary

The NASM manual adds:

In addition, current versions of NASM accept the prefix 0h for hexadecimal, 0d or 0t for decimal, 0o or 0q for octal, and 0b or 0y for binary.

TL;DR: While NASM supports both a b-suffix and a 0b-prefix for binary literals, YASM only supports the suffix variant. So 0b111 needs to be written as 111b.

Upvotes: 3

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