[9fans] Disassembler?

[9fans] Disassembler?

[Anant Narayanan]

Hi,

Is there a tool available which can convert plan 9 a.out executables
to plan 9 assembly code? I'd like to know how the C compiler stores
arguments for a system call on the stack for x86.

8c -S does not help, since all it displays is: `call print', instead
of what instructions are actually executed when print is called.

Regards,
Anant

Re: [9fans] Disassembler?

[Pietro Gagliardi]

On May 2, 2008, at 6:14 AM, Anant Narayanan wrote:

> Hi,
>
> Is there a tool available which can convert plan 9 a.out executables
> to plan 9 assembly code? I'd like to know how the C compiler stores
> arguments for a system call on the stack for x86.
>
> 8c -S does not help, since all it displays is: `call print', instead
> of what instructions are actually executed when print is called.
>
> Regards,
> Anant
>
>

8c doesn't use push or pop. It stores values directly onto the stack
with MOVL AX, 4(SP) for the second argument. This implies you'll need
to allocate enough stack space:

	TEXT x, 0, $12

will give you enough for 2 arguments (don't tell me why not 3).

The compilers push arguments left to right every 4 bytes.

Re: [9fans] Disassembler?

[erik quanstrom]

> Hi,
>
> Is there a tool available which can convert plan 9 a.out executables
> to plan 9 assembly code? I'd like to know how the C compiler stores
> arguments for a system call on the stack for x86.
>
> 8c -S does not help, since all it displays is: `call print', instead
> of what instructions are actually executed when print is called.
>
> Regards,
> Anant

if i understand you correctly, that's because print is in a library
and is called not inline.  you can use acid on the executable to
	asm(print)
which disassembles code starting at print.

- erik

Re: [9fans] Disassembler?

[Charles Forsyth]

i normally give the -a option to 8l(1)

Re: [9fans] Disassembler?

[Charles Forsyth]

> i normally give the -a option to 8l(1)

or use db(1) or acid(1)