Assembly incorrect when `.text` section start address is sufficiently high

[mortbopet]

As found in #150, setting the .text section start address to some sufficiently high address, e.g. 0xFFFFFFFF, the symbols of the input assembly code are emitted starting from 0xFFFFFFFFFFFFFFFF, and the (dis)assembled code is never shown in the programming viewer.

This issue is partly within the assembler, and partly within the fact that (at least on 32-bit systems), it should be invalid to set the .text section start address s.t.:

(start address + program size) > 0xFFFFFFFF