amxmodx/amxmodx/natives-amd64.asm
2014-08-04 13:18:19 -05:00

96 lines
2.4 KiB
NASM
Executable File

; vim: set ts=4 sw=4 tw=99 noet ft=nasm:
;
; AMX Mod X, based on AMX Mod by Aleksander Naszko ("OLO").
; Copyright (C) The AMX Mod X Development Team.
;
; This software is licensed under the GNU General Public License, version 3 or higher.
; Additional exceptions apply. For full license details, see LICENSE.txt or visit:
; https://alliedmods.net/amxmodx-license
;
; register_native functions for amd64
; Based on the concept by Julien "dJeyL" Laurent
; Thanks to T(+)rget for pushing to implement this
;
;;Initializes the global variable
BITS 64
section .text
global amxx_DynaInit, _amxx_DynaInit
;void amxx_DynaInit(void *ptr);
amxx_DynaInit:
_amxx_DynaInit:
mov [GLOBAL_GATE wrt rip], rdi
ret
;;Assembles the gateway function
global amxx_DynaMake, _amxx_DynaMake
;int amxx_DynaMake(char *buffer, int id);
amxx_DynaMake:
_amxx_DynaMake:
;we're not damaging the stack I think so we should be safe with no prologue
;save these two we're about to destroy them
push rsi ;push id
push rdi ;push buffer
mov rsi, _amxx_DynaFuncStart
mov rcx, _amxx_DynaFuncEnd - _amxx_DynaFuncStart
cld ;clear direction flag (just in case)
rep movsb
pop rdi ;get buffer as destination
pop rax ;get id
;align us to mov rsi, 1234... - on x86-64 this is 2 bytes after the differential
add rdi, (_amxx_DynaFuncStart.move-_amxx_DynaFuncStart) + 2
mov [rdi], qword rax
;align rdi to the call
add rdi, (_amxx_DynaFuncStart.call-_amxx_DynaFuncStart.move)
mov rax, qword [GLOBAL_GATE wrt rip]
;copy the real address
mov [rdi], rax
ret
;;The gateway function we will re-assemble
;; This is similar to dJeyL's but a tad more elegant, as it's written in pure assembly
;; and NASM > GAS :')
global amxx_DynaFunc, _amxx_DynaFunc
;int amxx_DynaFunc(AMX *amx, cell *params);
amxx_DynaFunc:
_amxx_DynaFunc:
_amxx_DynaFuncStart:
push rbp
mov rbp, rsp
;we're given an amx and params... we're also hardcoded for this though:
mov rdx, rsi ;move 2nd param to 3rd
mov rsi, rdi ;move 1st param to 2nd
;this old trick, we'll move in the real pointer in a bit.
.move:
mov rdi, qword 1234567812345678h
.call:
mov rcx, qword 1234567812345678h
call rcx
pop rbp
ret
_amxx_DynaFuncEnd:
;;Just returns the buffer size required
global _amxx_DynaCodesize, amxx_DynaCodesize
;int amxx_DynaCodesize()
amxx_DynaCodesize:
_amxx_DynaCodesize:
; on x86-64 this is 34 bytes
mov rax, _amxx_DynaFuncEnd - _amxx_DynaFuncStart
ret
section .data
GLOBAL_GATE DQ 0