From c41979dd84861a5f9026352f63702ebe2c2b7b8b Mon Sep 17 00:00:00 2001
From: Daggolin <Daggolin@Gmx.de>
Date: Thu, 2 Nov 2023 23:50:06 +0100
Subject: [PATCH] Add win32/q3asm.asm from jk2mv for MSVC builds.

---
 CMakeLists.txt         |  5 +++
 codemp/CMakeLists.txt  |  6 +++
 codemp/win32/q3asm.asm | 83 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 94 insertions(+)
 create mode 100644 codemp/win32/q3asm.asm

diff --git a/CMakeLists.txt b/CMakeLists.txt
index e25fea87bc..46083ded93 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -102,6 +102,11 @@ list(INSERT CMAKE_MODULE_PATH 0 "${CMAKE_SOURCE_DIR}/cmake/Modules")
 # ${Architecture} must match ARCH_STRING in q_platform.h,
 # and is used in DLL names (jagamex86.dll, jagamex86.dylib, jagamei386.so).
 if(WIN32)
+
+	if(MSVC)
+		enable_language(ASM_MASM)
+	endif()
+
 	set(X86 ON)
 	if(CMAKE_SIZEOF_VOID_P MATCHES "8")
 		set(Architecture "x86_64")
diff --git a/codemp/CMakeLists.txt b/codemp/CMakeLists.txt
index c043dd22a6..bcb0b5f5d4 100644
--- a/codemp/CMakeLists.txt
+++ b/codemp/CMakeLists.txt
@@ -271,6 +271,12 @@ if(BuildMPEngine OR BuildMPDed)
 		)
 	endif()
 
+	if(MSVC)
+		set(MPEngineAndDedCommonFiles ${MPEngineAndDedCommonFiles}
+			"${MPDir}/win32/q3asm.asm"
+		)
+	endif()
+
 	if(WIN32)
 		set(MPEngineAndDedCommonFiles ${MPEngineAndDedCommonFiles})
 	endif(WIN32)
diff --git a/codemp/win32/q3asm.asm b/codemp/win32/q3asm.asm
new file mode 100644
index 0000000000..b64f07a51e
--- /dev/null
+++ b/codemp/win32/q3asm.asm
@@ -0,0 +1,83 @@
+; ===========================================================================
+; Copyright (C) 2011 Thilo Schulz <thilo@tjps.eu>
+; 
+; This file is part of Quake III Arena source code.
+; 
+; Quake III Arena source code is free software; you can redistribute it
+; and/or modify it under the terms of the GNU General Public License as
+; published by the Free Software Foundation; either version 2 of the License,
+; or (at your option) any later version.
+; 
+; Quake III Arena source code is distributed in the hope that it will be
+; useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+; GNU General Public License for more details.
+; 
+; You should have received a copy of the GNU General Public License
+; along with Quake III Arena source code; if not, write to the Free Software
+; Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+; ===========================================================================
+
+; MASM ftol conversion functions using SSE or FPU
+; assume __cdecl calling convention is being used for x86, __fastcall for x64
+
+IFNDEF WIN64
+.686p
+.xmm
+.model flat, c
+ENDIF
+
+.data
+ALIGN 16
+ssemask DWORD 0FFFFFFFFh, 0FFFFFFFFh, 0FFFFFFFFh, 00000000h
+
+.code
+
+; dummy
+IFNDEF WIN64
+	.safeseh SEH_handler
+	SEH_handler   proc
+		ret
+	SEH_handler   endp
+ENDIF
+
+IFDEF WIN64
+	Q_VMftol PROC
+		movss xmm0, dword ptr [rdi + rbx * 4]
+		cvttss2si eax, xmm0
+		ret
+	Q_VMftol ENDP
+
+	qvmcall64 PROC
+		push rsi					; push non-volatile registers to stack
+		push rdi
+		push rbx
+		push rcx					; need to save pointer in rcx so we can write back the programData value to caller
+
+		; registers r8 and r9 have correct value already thanx to __fastcall
+		xor rbx, rbx				; opStackOfs starts out being 0
+		mov rdi, rdx				; opStack
+		mov esi, dword ptr [rcx]	; programStack
+
+		call qword ptr [r8]			; instructionPointers[0] is also the entry point
+
+		pop rcx
+
+		mov dword ptr [rcx], esi	; write back the programStack value
+		mov al, bl					; return opStack offset
+
+		pop rbx
+		pop rdi
+		pop rsi
+
+		ret
+	qvmcall64 ENDP
+ELSE
+	Q_VMftol PROC
+		movss xmm0, dword ptr [edi + ebx * 4]
+		cvttss2si eax, xmm0
+		ret
+	Q_VMftol ENDP
+ENDIF
+
+end