What is d_main.cpp and where is it?

[EimGhey]

I need to edit my d_main.cpp since it doesn't support Floating Point Operations.  I am installing a Program on my Raspberry Pi and keep getting Floating Point Exceptions.

[BC_Programmer]

As you've left us to guess, I can only suppose  that d_main.cpp is part of ZDoom.  I can find no references to this particular issue so you'll probably want to provide more details. A Floating Point Exception would be when the program performs a floating point operation unsupported on the hardware.

d_main.cpp itself can be acquired as part of the source code to the program in question.

[Geek-9pm]

doesn't support Floating Point Operations. 

Does that mean Raspberry Pi does not have the hardware?
That is a very minimal controller that is being used as a PC. It is not designed to do all the things a desktop might need to do.
Without doing research, I think it will not do loading point for two or three reasons.
1. It is a minimal CPU with no math chip.
2. It task almost  a thousand lines of code to do that in software.
3. Anybody who needs floating pint in a tiny  package needs to rethink the design.

Of course, you could interface a FPU as an external module.
OR: Look here:
http://raspberrypi.stackexchange.com/questions/545/does-the-raspberry-pi-have-hardware-floating-point-support

[EimGhey]

Okay the I figured out where it was now why is ZDoom still not installing?

[Geek-9pm]

This might be relevant.
http://doomwiki.org/wiki/Raspberry_Pi

The shareware version of Doom was used during development of the Raspberry Pi in its benchmarking tests, and was useful in debugging compilation issues when porting software to the Raspberry Pi's ARM1176JZF-S, a relatively rare ARMv6 variant. Chocolate Doom was the only source port available on the official Raspberry Pi Store until its closure in February 2016.

Note: ARMv6 variant. This might  mean the code is not portable for versions of Raspberry Pi. See the site above and find somebody there who knows.