diff --git a/cad/abc/Makefile b/cad/abc/Makefile
index 04094a829cf2..7a9c1ec9eb72 100644
--- a/cad/abc/Makefile
+++ b/cad/abc/Makefile
@@ -1,44 +1,47 @@
 PORTNAME=	abc
 DISTVERSION=	g20251226
 PORTEPOCH=	1
 CATEGORIES=	cad
 
 MAINTAINER=	alven@FreeBSD.org
 COMMENT=	System for sequential synthesis and verification
 WWW=		https://people.eecs.berkeley.edu/~alanmi/abc/ \
 		https://github.com/berkeley-abc/abc/
 
 LICENSE=	MIT
 LICENSE_FILE=	${WRKSRC}/copyright.txt
 
+NOT_FOR_ARCHS=	i386
+NOT_FOR_ARCHS_REASON=	__int128 is not supported on this target
+
 BUILD_DEPENDS=	gmake:devel/gmake
 
 USES=		cmake
 USE_GITHUB=	yes
 GH_ACCOUNT=	berkeley-abc
 GH_TAGNAME=	91e806ff
 USE_LDCONFIG=	yes
 
 CMAKE_ON=	ABC_SKIP_TESTS
 
 BINARY_ALIAS=	make=${GMAKE}
 
 PLIST_FILES=	bin/${PORTNAME} \
 		lib/lib${PORTNAME}.so
 
 OPTIONS_DEFINE=		READLINE THREADS
 OPTIONS_DEFAULT=	READLINE THREADS
 
 READLINE_USES=			readline
 READLINE_CONFIGURE_ENV=		ABC_READLINE_LIBRARIES="-L${LOCALBASE}/lib -lreadline"
 READLINE_CONFIGURE_ENV_OFF=	ABC_USE_NO_READLINE=1
 
 THREADS_CONFIGURE_ENV_OFF=	ABC_USE_NO_PTHREADS=1
 
 do-install: # https://github.com/berkeley-abc/abc/issues/71
 	${INSTALL_PROGRAM} ${BUILD_WRKSRC}/${PORTNAME} \
 		${STAGEDIR}${PREFIX}/bin
 	${INSTALL_LIB} ${BUILD_WRKSRC}/lib${PORTNAME}.so \
 		${STAGEDIR}${PREFIX}/lib
 
 .include <bsd.port.mk>