FASM problems with procedures

I decided to understand the assembler (I chose FASM because everything just works out of the box), while writing "Hello World!" the question arose, why are we not actually working with the following code

format PE64 Console

entry main

include 'win64a.inc'

section '.data' data readable writeable
	hello2 db 'hello world!',0 

section '.bss' data readable writeable
	StandardHandle rd 1
	Written rd 1

section '.code' code readable writeable executable

	stdcall test_proc, 11
	invoke ExitProcess, 0

proc test_proc, ms
	invoke GetStdHandle, STD_OUTPUT_HANDLE
	mov [StandardHandle], eax;getting handle

	push rbx
	invoke WriteFile, [StandardHandle], hello2, 1, Written, 0
	mov rbx, qword ptr ms
	invoke WriteFile, [StandardHandle], hello2, 2, Written, 0
	invoke WriteFile, [StandardHandle], hello2, rbx, Written, 0
	invoke WriteFile, [StandardHandle], hello2, 3, Written, 0

	pop rbx


section '.idata' data import readable
		library kernel, 'kernel32.dll'

		import kernel,\
				GetStdHandle, 'GetStdHandle',\
				ExitProcess, 'ExitProcess',\
				WriteFile, 'WriteFile'

It reaches 3 calls to WriteFile and does not display anything on it, although the current output works. The salt itself is that the rbx register is not empty, an incomprehensible value is written into it (not what we passed). I can't understand anything...

1 Like

Why do you expect hello2 + rbx to be a valid pointer then?

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