From 5e09cca9640f9a51c42a5364c8d0d4d57cc38d37 Mon Sep 17 00:00:00 2001
From: Alan Mishchenko <alanmi@berkeley.edu>
Date: Sat, 9 Aug 2025 14:46:45 -0700
Subject: [PATCH] Handing the case of signed comparators.

---
 src/aig/gia/giaGen.c | 13 ++++++++++---
 src/base/abci/abc.c  | 18 +++++++++++-------
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/src/aig/gia/giaGen.c b/src/aig/gia/giaGen.c
index 088b64191..c22cb21f8 100644
--- a/src/aig/gia/giaGen.c
+++ b/src/aig/gia/giaGen.c
@@ -1192,9 +1192,9 @@ Gia_Man_t * Gia_ManGenNeuron( char * pFileName, int nIBits, int nLutSize, int fD
   SeeAlso     []
 
 ***********************************************************************/
-Gia_Man_t * Gia_ManDupGenComp( int nBits, int fInterleave )
+Gia_Man_t * Gia_ManDupGenComp( int nBits, int fInterleave, int fSigned )
 {
-    Gia_Man_t * pNew, * pTemp; int i, iLit = 1;
+    Gia_Man_t * pNew, * pTemp; int i, iLit = 1, iLitXor = 0, iLitB = 0;
     Vec_Int_t * vBitsA = Vec_IntAlloc( nBits + 1 );
     Vec_Int_t * vBitsB = Vec_IntAlloc( nBits + 1 );
     pNew = Gia_ManStart( 6*nBits+10 );
@@ -1211,6 +1211,10 @@ Gia_Man_t * Gia_ManDupGenComp( int nBits, int fInterleave )
         for ( i = 0; i < nBits; i++ )
             Vec_IntPush( vBitsB, Gia_ManAppendCi(pNew) );
     }
+    if ( fSigned ) {
+        iLitXor = Gia_ManHashXor( pNew, Vec_IntPop(vBitsA), (iLitB = Vec_IntPop(vBitsB)) );
+        nBits--;
+    }
     Vec_IntPush( vBitsA, 0 );
     Vec_IntPush( vBitsB, 0 );
     for ( i = 0; i < nBits; i++ ) {
@@ -1227,7 +1231,10 @@ Gia_Man_t * Gia_ManDupGenComp( int nBits, int fInterleave )
         int iOrLit  = Gia_ManHashOr(pNew, iOrLit0, iOrLit1 );
         iLit = Gia_ManHashOr(pNew, Abc_LitNot(iLit), iOrLit );
     }
-    Gia_ManAppendCo( pNew, Abc_LitNotCond(iLit, nBits&1) );
+    iLit = Abc_LitNotCond(iLit, nBits&1);
+    if ( fSigned ) 
+        iLit = Gia_ManHashMux(pNew, iLitXor, iLitB, iLit );
+    Gia_ManAppendCo( pNew, iLit );
     pNew = Gia_ManCleanup( pTemp = pNew );
     Gia_ManStop( pTemp );
     Vec_IntFree( vBitsA );
diff --git a/src/base/abci/abc.c b/src/base/abci/abc.c
index d9b688b9b..8f17275bf 100644
--- a/src/base/abci/abc.c
+++ b/src/base/abci/abc.c
@@ -56446,11 +56446,11 @@ usage:
 ***********************************************************************/
 int Abc_CommandAbc9GenComp( Abc_Frame_t * pAbc, int argc, char ** argv )
 {
-    extern Gia_Man_t * Gia_ManDupGenComp( int nBits, int fInterleave );
+    extern Gia_Man_t * Gia_ManDupGenComp( int nBits, int fInterleave, int fSigned );
     Gia_Man_t * pTemp = NULL;
-    int c, nBits = 0, fInter = 0, fVerbose = 0;
+    int c, nBits = 4, fInter = 0, fSigned = 0, fVerbose = 0;
     Extra_UtilGetoptReset();
-    while ( ( c = Extra_UtilGetopt( argc, argv, "Kivh" ) ) != EOF )
+    while ( ( c = Extra_UtilGetopt( argc, argv, "Kisvh" ) ) != EOF )
     {
         switch ( c )
         {
@@ -56468,6 +56468,9 @@ int Abc_CommandAbc9GenComp( Abc_Frame_t * pAbc, int argc, char ** argv )
         case 'i':
             fInter ^= 1;
             break;            
+        case 's':
+            fSigned ^= 1;
+            break;
         case 'v':
             fVerbose ^= 1;
             break;
@@ -56482,17 +56485,18 @@ int Abc_CommandAbc9GenComp( Abc_Frame_t * pAbc, int argc, char ** argv )
         Abc_Print( -1, "Abc_CommandAbc9GenComp(): The number of inputs should be defined on the command line \"-K num\".\n" );
         return 0;            
     }    
-    pTemp = Gia_ManDupGenComp( nBits, fInter );
+    pTemp = Gia_ManDupGenComp( nBits, fInter, fSigned );
     Abc_FrameUpdateGia( pAbc, pTemp );
     if ( fVerbose )
         Abc_Print( 1, "Generated %d-bit comparator.\n", nBits );
     return 0;
 
 usage:
-    Abc_Print( -2, "usage: &gencomp [-K <num>] [-ivh]\n" );
-    Abc_Print( -2, "\t         generates the comparator\n" );
-    Abc_Print( -2, "\t-K num : the number of control inputs [default = undefined]\n" );
+    Abc_Print( -2, "usage: &gencomp [-K <num>] [-isvh]\n" );
+    Abc_Print( -2, "\t         generates the comparator (a > b)\n" );
+    Abc_Print( -2, "\t-K num : the bitwidth of the inputs [default = %d]\n", nBits );
     Abc_Print( -2, "\t-i     : toggles using interleaved variable ordering [default = %s]\n", fInter ? "yes": "no" );
+    Abc_Print( -2, "\t-s     : toggles generating signed comparator [default = %s]\n", fSigned ? "yes": "no" );
     Abc_Print( -2, "\t-v     : toggles printing verbose information [default = %s]\n", fVerbose ? "yes": "no" );
     Abc_Print( -2, "\t-h     : print the command usage\n");
     return 1;