diff --git a/library/sas_cxv52.asm b/library/sas_cxv52.asm
new file mode 100644
index 0000000..dae5139
--- /dev/null
+++ b/library/sas_cxv52.asm
@@ -0,0 +1,106 @@
+*
+* :ts=8
+*
+* Adapted from reassembled SAS/C runtime library code.
+*
+* Portable ISO 'C' (1994) runtime library for the Amiga computer
+* Copyright (c) 2002-2015 by Olaf Barthel <obarthel (at) gmx.net>
+* All rights reserved.
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions
+* are met:
+*
+*   - Redistributions of source code must retain the above copyright
+*     notice, this list of conditions and the following disclaimer.
+*
+*   - Neither the name of Olaf Barthel nor the names of contributors
+*     may be used to endorse or promote products derived from this
+*     software without specific prior written permission.
+*
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+* POSSIBILITY OF SUCH DAMAGE.
+*
+
+	xdef	__CXV52
+	xdef	__CXV53
+
+	xref	__CXFERR
+
+	section	text,code
+
+__CXV52:
+
+	MOVEM.L	D2/D3,-(SP)
+	MOVEQ	#-1,D3
+	MOVE.L	D0,D2
+	BPL.W	lab04A
+	CMPI.L	#$BFF00000,D0
+	BCS.W	lab07A
+	MOVEM.L	D0/D1/A0/A1,-(SP)
+	PEA	(2).L
+	JSR	__CXFERR
+	ADDQ.W	#4,SP
+	MOVEM.L	(SP)+,D0/D1/A0/A1
+	BRA.W	lab07A
+
+__CXV53:
+
+	MOVEM.L	D2/D3,-(SP)
+	MOVE.L	#$7FFFFFFF,D3
+	MOVE.L	D0,D2
+	BPL.W	lab04A
+	ADDQ.L	#1,D3
+	EOR.L	D3,D0
+lab04A:	SWAP	D0
+	MOVE.W	D0,D2
+	ANDI.W	#$7FF0,D2
+	EOR.W	D2,D0
+	SUBI.W	#$3FF0,D2
+	BLT.W	lab07A
+	EORI.W	#$10,D0
+	SWAP	D0
+	ASR.W	#4,D2
+	SUBI.W	#$14,D2
+	BGT.W	lab09A
+	NEG.W	D2
+	LSR.L	D2,D0
+	TST.L	D2
+	BMI.W	lab0B2
+	BRA.W	lab0B4
+
+lab07A:	MOVEQ	#0,D0
+	BRA.W	lab0B4
+
+lab080:	MOVEM.L	D0/D1/A0/A1,-(SP)
+	PEA	(2).L
+	JSR	__CXFERR
+	ADDQ.W	#4,SP
+	MOVEM.L	(SP)+,D0/D1/A0/A1
+	MOVE.L	D3,D0
+	BRA.W	lab0B4
+
+lab09A:	CMPI.W	#11,D2
+	BGT.B	lab080
+	EOR.L	D1,D0
+	ROL.L	D2,D0
+	LSL.L	D2,D1
+	EOR.L	D1,D0
+	CMP.L	D3,D0
+	BHI.B	lab080
+	TST.L	D2
+	BPL.W	lab0B4
+lab0B2:	NEG.L	D0
+lab0B4:	MOVEM.L	(SP)+,D2/D3
+	RTS
+
+	end