I just started learning ASM, I have C experience but I guess it doesn't matter. Anyway how can I initialize a 12 elements array of DT to 0s, and how not to initialize it?
I use FASM.
Asked
Active
Viewed 2,816 times
4
-
2The language is called "assembly" and the piece of system software that turns it into an executable is called an "assembler". – Sparafusile Jul 26 '11 at 18:25
2 Answers
1
Since arrays are just a contiguous chunk of memory with elements one after the other, you can do something like this in NASM (not sure if FASM supports the times directive, but you could try):
my_array:
times 12 dt 0.0
That is expanded out when your source is assembled to:
my_array:
dt 0.0
dt 0.0
dt 0.0
dt 0.0
dt 0.0
dt 0.0
dt 0.0
dt 0.0
dt 0.0
dt 0.0
dt 0.0
dt 0.0
-
-
Oh, yeah it supports times directive but i don't know why I can't use it with dt variable x_x – adad Jul 17 '11 at 11:07
-
1You can't initialize tbytes to integers, only to floats: *times 12 dt 0.0* – Jens Björnhager Jul 19 '11 at 10:23
0
Just use the reserve data directive and reserve 12 tbytes:
array: rt 12
Jens Björnhager
- 5,632
- 3
- 27
- 47
-
-
And then can I normally reffer to that bytes like that :mov eax, [array+10](second element)? – adad Jul 17 '11 at 11:27
-
Yes, but as you are working with tbytes perhaps you meant something like fld tbyte [array+10]? – Jens Björnhager Jul 17 '11 at 11:32
-
-
eax is 32 bits, you can only fit four bytes there. tbytes are mostly used for 80-bit full-precision floating-point numbers. – Jens Björnhager Jul 17 '11 at 11:35
-
Ahh, I see and if I want to put data to second element? mov [array+10], 2 is not working – adad Jul 17 '11 at 11:42
-
You need to set the operand size for immediate-to-memory transfers. For 32 bit: mov dword [array+10], 2 – Jens Björnhager Jul 17 '11 at 12:10
-
Damn it I had it like that but I thought putting dw will be enough. Thanks – adad Jul 17 '11 at 12:13