5. Code Generation Differences

JWasm might generate slightly different code than Masm on some occasions. Commandline option -Zg should eliminate most of these differences. However, some differences are due to fixed Masm bugs (see below), in which case option -Zg won't have any effect.

For a few instructions, the encoding differs between Masm versions.

Example:

    cmp al,dl

is encoded 38 D0 in Masm v6, but 3A C2 in Masm v8. In such cases, JWasm will prefer to copy the encoding of Masm v8.