[Nasm-bugs] [Bug 3392403] New: missing documentation for specifying size, e.g. mov *byte* [addr], imm

no-reply at bugzilla-nasm.gorcunov.org no-reply at bugzilla-nasm.gorcunov.org
Fri Apr 28 04:43:13 PDT 2017


            Bug ID: 3392403
           Summary: missing documentation for specifying size, e.g. mov
                    *byte* [addr], imm
           Product: NASM
           Version: 2.12.xx
          Hardware: All
                OS: All
            Status: OPEN
          Severity: normal
          Priority: Medium
         Component: Assembler
          Assignee: nobody at nasm.us
          Reporter: eekee57 at fastmail.fm
                CC: gorcunov at gmail.com, hpa at zytor.com, nasm-bugs at nasm.us

i'm just starting out with 8086 assembler. i find 90% of tutorials extremely
confusing, so i go straight for references and manuals; in this case intel's
instruction set reference and of course nasm's manual. for the most part i've
got on well with just these two, but when i needed to know how to specify the
data size in assembly language when there were no registers involved, i didn't
find the answer in either document. (i'm not sure the instruction set reference
is concerned with assembly language.) i searched nasm's manual as thoroughly as
i could, finding size specifiers for addressing modes and operand sizes, (a16,
o32, etc,) but attempting to adapt those specifiers for the 8-bit mov i needed
simply raised errors. 

i asked about it in irc, and was told of the correct form. i had:
    mov [addr], 0h10
i needed:
    mov byte [addr], 0h10
nothing in nasm's manual told me of the latter form.

i'd be happy if i could continue to get on with just these two documents. :)
besides, seeing as address- and operand-size prefixes are documented in nasm's
manual (albeit barely in the case of operand prefixes), i think it makes some
sense to document these other size qualifiers too.

i have a bigger problem with idiv, where i need to specify imm16 not imm8,
(because the results end up in different registers for these different sizes,)
but no placement of 'word' or 'o16' is accepted. i'm unsure whether to file
this as a separate bug.

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