Calling realloc from assembly block

[Zamaster]

I assumed it would be something like:

Code: Select all

asm
	push		ebx 			'num bytes
	push		ecx 			'address
	call		reallocate
	add     	esp,                	8
	mov		ecx,			eax	'get result of function call
end asm

But I get a big 'ol crash. What should I have done differently? Thanks!

[Zamaster]

Even weirder, if I debug it in x32dbg it runs without a problem (can even print stuff after the block), so whats wrong here? Here's the source listing from the member function making the call:

Code: Select all

    sub DArray.reserve naked cdecl(byref _this as DArray, _elements as size_t)
        asm
        #ifdef __FB_64BIT__

        #else
                mov     edx,                dword ptr [esp+4]
                mov     ecx,                dword ptr [edx+8]
                mov     eax,                dword ptr [edx+4]
                add     eax,                dword ptr [esp+8]
                cmp     eax,                ecx
                jb      dsm_darray_reserve_return_32
            dsm_darray_reserve_doublememoryloop_32:
                shl     ecx,                1
                cmp     ecx,                eax
                jb      dsm_darray_reserve_doublememoryloop_32
                push    ecx
                push    dword ptr [edx]
                call    reallocate
                add     esp,                8
                mov     dword ptr [edx],    eax
            dsm_darray_reserve_return_32:
                ret
        #endif
        end asm
    end sub

[Zamaster]

Okay okay I'm dumb yeah I see it HA, forgive me I was having a special moment

[D.J.Peters]

Normaly there isn't a "reallocate"
all exported FB stuff has an "fb_" in front so far I remember.
try "fb_reallocate" instead

Joshy

[Zamaster]

actually, "call reallocate" works just fine!

[D.J.Peters]

@Zamaster Yes but reallocate calls than fb_reallocate so if you do low level assembler coding why not using fb_allocate directly ?
If you use the FB runtime directly (it's C calling) you don't need to restore the stack from assembler :-)
How ever have fun with assembler.

Joshy

[Zamaster]

I didn't even know about FB exported functions until you said so! I'll certainly keep that in mind going forward. I ended up calling a different procedure inside the routine anyway, mostly wanted to keep the common case fast since reallocates should be rare in this code.

[dkl]

FB's reallocate() is just an alias for the CRT realloc(), and fbc even does this replacement for you in the inline ASM (you can check by compiling with -R and looking at the generated .asm file).