On Sunday, 12 November 2017 at 11:01:39 UTC, Dibyendu Majumdar
wrote:
Hi,
I have recently started work on building a VM for Lua (actually
a derivative of Lua) in X86-64 assembly. I am using the dynasm
tool that is part of LuaJIT. I was wondering whether I could
also write this in D's inline assembly perhaps, but there is
one aspect that I am not sure how to do.
The assembly code uses static allocation of registers, but
because of the differences in how registers are used in Win64
versus Unix X64 - different registers are assigned depending on
the architecture. dynasm makes this easy to do using macros;
e.g. below.
|.if X64WIN
|.define CARG1, rcx // x64/WIN64 C call arguments.
|.define CARG2, rdx
|.define CARG3, r8
|.define CARG4, r9
|.else
|.define CARG1, rdi // x64/POSIX C call arguments.
|.define CARG2, rsi
|.define CARG3, rdx
|.define CARG4, rcx
|.endif
With above in place, the code can use the mnemonics to refer to
the registers rather than the registers themselves. This allows
the assembly code to be coded once for both architectures.
How would one do this in D inline assembly?
Thanks and Regards
Dibyendu
You could do it with a mixin, it would be rather ugly though. Not
sure of another way off the top of my head.
