Thread: ASM w/ C++ issues

Originally Posted by Dino

I get the following error when running the above:

Code:

[Session started at 2008-09-19 17:16:13 -0500.]

c_asm_misc has exited due to signal 4 (SIGILL).

Intel Dual Core Xeon Mac.

With what compiler and OS configuration? If it's 64-bit, then it won't be right, since push ECX will actually push a sign-extended 64-bit version of ECX.

--
Mats

Ah. Mac OS X (Tiger) 10.4.11 with Intel Dual Core Xeon processors.

Originally Posted by matsp

movzx - Move with Zero Extension: It loads the 16-bit value into a 32-bit register, and fills the remaining 16 bits with zero. It's counterpart for signed numbers is movsx, which fills the upper 16 bits with the content of bit 15 of the low 16 bits.

Hmmm. But doesn't it just usually work to move a number directly into a register without 0-ing? I don't know if I've tried...

jae - Jump Above or Equal. It's the same as JGE but for unsigned numbers.

Aha!
But then again, I've never encountered JGE before...

And I can't continue to use ECX after the call, since it's one of the registers that can be used in the callee without preservation, so it would require another load before inc can be used on it. Of course, I could have picked another register...

Another register is what I was thinking ;)

And I never knew inc could work with other things than registers... that's cool.
Thanks for the information. One step closer to an assembly expert