1 files changed, 107 insertions, 0 deletions
diff --git a/src/asm/snapvector.asm b/src/asm/snapvector.asm
new file mode 100644
index 00000000..87c77372
--- /dev/null
+++ b/src/asm/snapvector.asm
@@ -0,0 +1,107 @@
+; ===========================================================================
+; 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 version of snapvector conversion function using SSE or FPU
+; assume __cdecl calling convention is being used for x86, __fastcall for x64
+;
+; function prototype:
+; void qsnapvector(vec3_t vec)
+
+IFNDEF idx64
+.model flat, c
+ENDIF
+
+.data
+
+  ALIGN 16
+  ssemask DWORD 0FFFFFFFFh, 0FFFFFFFFh, 0FFFFFFFFh, 00000000h
+  ssecw DWORD 00001F80h
+
+IFNDEF idx64
+  fpucw WORD 037Fh
+ENDIF
+
+.code
+
+IFDEF idx64
+; qsnapvector using SSE
+
+  qsnapvectorsse PROC
+    sub rsp, 4
+	stmxcsr [rsp]				; save SSE control word
+	ldmxcsr ssecw				; set to round nearest
+
+    push rdi
+	mov rdi, rcx				; maskmovdqu uses rdi as implicit memory operand
+	movaps xmm1, ssemask		; initialize the mask register for maskmovdqu
+    movups xmm0, [rdi]			; here is stored our vector. Read 4 values in one go
+	cvtps2dq xmm0, xmm0			; convert 4 single fp to int
+	cvtdq2ps xmm0, xmm0			; convert 4 int to single fp
+	maskmovdqu xmm0, xmm1		; write 3 values back to memory
+	pop rdi
+
+	ldmxcsr [rsp]				; restore sse control word to old value
+	add rsp, 4
+	ret
+  qsnapvectorsse ENDP
+
+ELSE
+
+  qsnapvectorsse PROC
+	sub esp, 4
+	stmxcsr [esp]				; save SSE control word
+	ldmxcsr ssecw				; set to round nearest
+
+    push edi
+	mov edi, dword ptr 12[esp]	; maskmovdqu uses edi as implicit memory operand
+	movaps xmm1, ssemask		; initialize the mask register for maskmovdqu
+    movups xmm0, [edi]			; here is stored our vector. Read 4 values in one go
+	cvtps2dq xmm0, xmm0			; convert 4 single fp to int
+	cvtdq2ps xmm0, xmm0			; convert 4 int to single fp
+	maskmovdqu xmm0, xmm1		; write 3 values back to memory
+	pop edi
+
+	ldmxcsr [esp]				; restore sse control word to old value
+	add esp, 4
+	ret
+  qsnapvectorsse ENDP
+
+  qroundx87 macro src
+	fld dword ptr src
+	fistp dword ptr src
+	fild dword ptr src
+	fstp dword ptr src
+  endm    
+
+  qsnapvectorx87 PROC
+	mov eax, dword ptr 4[esp]
+	sub esp, 2
+	fnstcw word ptr [esp]
+	fldcw fpucw
+	qroundx87 [eax]
+	qroundx87 4[eax]
+	qroundx87 8[eax]
+	fldcw [esp]
+	add esp, 2
+  qsnapvectorx87 ENDP
+
+ENDIF
+
+end