--- tme/ic/m68k/m68k-insns-auto.sh	2018/04/24 16:37:52	1.1.1.1
+++ tme/ic/m68k/m68k-insns-auto.sh	2018/04/24 16:39:03	1.1.1.2
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# $Id: m68k-insns-auto.sh,v 1.1.1.1 2018/04/24 16:37:52 root Exp $
+# $Id: m68k-insns-auto.sh,v 1.1.1.2 2018/04/24 16:39:03 root Exp $
 
 # ic/m68k/m68k-insns-auto.sh - automatically generates C code 
 # for many m68k emulation instructions:
@@ -48,7 +48,7 @@ done
 PROG=`basename $0`
 cat <<EOF
 /* automatically generated by $PROG, do not edit! */
-_TME_RCSID("\$Id: m68k-insns-auto.sh,v 1.1.1.1 2018/04/24 16:37:52 root Exp $");
+_TME_RCSID("\$Id: m68k-insns-auto.sh,v 1.1.1.2 2018/04/24 16:39:03 root Exp $");
 
 EOF
 if $header; then :; else
@@ -421,7 +421,7 @@ for size in 8 16 32; do
 	    sign=u
 	    case "${name}" in
 	    asr) sign= ;;
-	    asl) echo "  tme_uint${size}_t sign_bits;" ;;
+	    asl) echo "  tme_uint${size}_t sign_bits, sign_bits_mask;" ;;
 	    rox[lr]) echo "  tme_uint8_t xbit;" ;;
 	    *) ;;
 	    esac
@@ -465,27 +465,28 @@ for size in 8 16 32; do
 		    echo "       shifting in order to generate V."
 		    echo ""
 		    echo "       in general, the idea is to get all of the bits that will ever"
-		    echo "       appear in the sign position into sign_bits; if sign_bits is"
-		    echo "       all-bits-one or all-bits zero, clear V, else set V.  a good trick"
-		    echo "       is that ((sign_bits + 1) & sign_bits) is nonzero iff all of the"
-		    echo "       bits in sign_bits are the same."
+		    echo "       appear in the sign position into sign_bits, with a mask in"
+		    echo "       sign_bits_mask.  if (sign_bits & sign_bits_mask) is zero or"
+		    echo "       sign_bits_mask, clear V, else set V."
 		    echo ""
-		    echo "       start by loading all of the operand into sign_bits."
+		    echo "       start by loading the operand into sign_bits and setting"
+		    echo "       sign_bits_mask to all-bits-one."
 		    echo ""
 		    echo "       if the shift count is exactly ${size} - 1, then all of the bits"
 		    echo "       of the operand will appear in the sign position."
 		    echo ""
 		    echo "       if the shift count is less than ${size} - 1, then some of the"
 		    echo "       less significant bits of the operand will never appear in the"
-		    echo "       sign position, so we can shift them off of sign_bits now."
+		    echo "       sign position, so we can shift sign_bits_mask to ignore them."
 		    echo ""
 		    echo "       if the shift count is greater than ${size} - 1, then all of the"
 		    echo "       bits in the operand, plus at least one zero bit, will appear in"
 		    echo "       the sign position.  the only way that the sign bit will never"
 		    echo "       change during the shift is if the operand was zero to begin with."
-		    echo "       we need to change sign_bits such that ((sign_bits + 1) &"
-		    echo "       sign_bits) will be zero iff the operand was zero to begin with."
-		    echo "       the magic below does just that: */"
+		    echo "       without any changes to sign_bits or sign_bits_mask, the final"
+		    echo "       test will always work, except when sign_bits is all-bits-one."
+		    echo "       the magic below clears the least-significant bit of sign_bits"
+		    echo "       iff sign_bits is all-bits-one: */"
 		    echo "    sign_bits = res;"
 		fi
 		echo "    if (63 > SHIFTMAX_INT${size}_T"
@@ -498,16 +499,17 @@ for size in 8 16 32; do
 		echo "    flags |= (flags * TME_M68K_FLAG_X);"
 		echo "    res <<= 1;"
 		if test ${name} = asl; then		
+		    echo "    sign_bits_mask = (tme_uint${size}_t) -1;"
 		    echo "    if (count != ${size} - 1) {"
 		    echo "      if (count < ${size}) {"
-		    echo "        sign_bits >>= ((${size} - 1) - count);"
+		    echo "        sign_bits_mask <<= ((${size} - 1) - count);"
 		    echo "      }"
 		    echo "      else {"
-		    echo "        sign_bits |= (sign_bits << 1);"
-		    echo "        sign_bits &= -2;"
+		    echo "        sign_bits ^= !(sign_bits + 1);"
 		    echo "      }"
 		    echo "    }"		    
-		    echo "    if ((sign_bits + 1) & sign_bits) {"
+		    echo "    sign_bits &= sign_bits_mask;"
+		    echo "    if (sign_bits != 0 && sign_bits != sign_bits_mask) {"
 		    echo "      flags |= TME_M68K_FLAG_V;"
 		    echo "    }"
 		fi
@@ -657,8 +659,6 @@ for size in 8 16 32; do
 	echo "  tme_uint32_t addend;"
 
 	echo ""
-	echo "  TME_M68K_INSN_CANFAULT;"
-	echo ""
 	echo "  /* figure out what direction to move in, and where to start from: */"
 	echo "  ea_mode = TME_FIELD_EXTRACTU(TME_M68K_INSN_OPCODE, 3, 3);"
 	echo "  direction = 1;"
@@ -677,6 +677,9 @@ for size in 8 16 32; do
 	echo ""
 	echo "  /* do the transfer: */"
 	echo "  mask = TME_M68K_INSN_SPECOP;"
+	echo "  if (mask != 0) {"
+	echo "    TME_M68K_INSN_CANFAULT;"
+	echo "  }"
 	echo "  for (bit = 1; bit != 0; bit <<= 1) {"
 	echo "    if (mask & bit) {"
 	if test $name = rm; then
@@ -1702,9 +1705,9 @@ for _sign in u s; do
 	echo "TME_M68K_INSN(tme_m68k_mul${_sign}${_size})"
 	echo "{"
  	if test $large = 64; then
-	    echo "#ifndef HAVE_UINT${large}_T"
+	    echo "#ifndef TME_HAVE_INT${large}_T"
 	    echo "  abort();"
-	    echo "#else /* HAVE_UINT${large}_T */"
+	    echo "#else /* TME_HAVE_INT${large}_T */"
 	    echo "  unsigned int flag_v;"
 	    echo "  int ireg_dh;"
 	fi
@@ -1744,8 +1747,11 @@ for _sign in u s; do
 	echo "  if (((tme_int${large}_t) res) < 0) flags |= TME_M68K_FLAG_N;"
 	echo "  if (res == 0) flags |= TME_M68K_FLAG_Z;"
 	if test $large = 64; then
-	    echo -n "  if (res > 0xffffffff"
-	    if test $_sign = s; then echo -n " || res < -2147483648"; fi
+	    if test $_sign = s; then
+		echo -n "  if (res > 0x7fffffffL || res < ((0L - 0x7fffffffL) - 1L)"
+	    else
+		echo -n "  if (res > 0xffffffffUL"
+	    fi
 	    echo ") flags |= flag_v;"
 	fi
 	echo "  ic->tme_m68k_ireg_ccr = flags;"
@@ -1753,7 +1759,7 @@ for _sign in u s; do
 	echo ""
 	echo "  TME_M68K_INSN_OK;"
  	if test $large = 64; then
-	    echo "#endif /* HAVE_UINT${large}_T */"
+	    echo "#endif /* TME_HAVE_INT${large}_T */"
 	fi
 	echo "}"
 
@@ -1762,9 +1768,9 @@ for _sign in u s; do
 	echo "TME_M68K_INSN(tme_m68k_div${_sign}${_size})"
 	echo "{"
  	if test $large = 64; then
-	    echo "#ifndef HAVE_UINT${large}_T"
+	    echo "#ifndef TME_HAVE_INT${large}_T"
 	    echo "  abort();"
-	    echo "#else /* HAVE_UINT${large}_T */"
+	    echo "#else /* TME_HAVE_INT${large}_T */"
 	    echo "  int ireg_dr;"
 	fi
 	echo "  int ireg_dq;"
@@ -1808,13 +1814,13 @@ for _sign in u s; do
 	echo ""
 	echo "  /* set the flags and return the quotient and remainder: */"
 	echo "  flags = ic->tme_m68k_ireg_ccr & TME_M68K_FLAG_X;"
-	echo -n "  if (quotient > 0xffff"
-	if test $small = 16; then
-	    if test $_sign = s; then echo -n " || quotient < -32768"; fi
-	else
-	    echo -n "ffff"
-	    if test $_sign = s; then echo -n " || quotient < -2147483648"; fi
-	fi
+	echo -n "  if ("
+	case "${small}${_sign}" in
+	16s) echo -n "quotient > 0x7fff || quotient < -32768" ;;
+	16u) echo -n "quotient > 0xffff" ;;
+	32s) echo -n "quotient > 0x7fffffffL || quotient < ((0L - 0x7fffffffL) - 1L)" ;;
+	32u) echo -n "quotient > 0xffffffffUL" ;;
+	esac
 	echo ") {"
 	echo "    flags |= TME_M68K_FLAG_V;"
 	echo "  }"
@@ -1835,7 +1841,7 @@ for _sign in u s; do
 	echo ""
 	echo "  TME_M68K_INSN_OK;"
  	if test $large = 64; then
-	    echo "#endif /* HAVE_UINT${large}_T */"
+	    echo "#endif /* TME_HAVE_INT${large}_T */"
 	fi
 	echo "}"