Handle is4 bytes without meaningful information in the bottom bits

Support is4 bytes without meaningful information in the bottom bits.
This is equivalent to /is4=0 for the assembler, but makes the bottom
bits don't care for the disassembler.

4 files changed, 40 insertions, 5 deletions

diff --git a/assemble.c b/assemble.c
index 1d440ea..c5f8172 100644
--- a/assemble.c
+++ b/assemble.c
@@ -46,9 +46,11 @@
  *                 operand 0..3.
  * \171		 - placement of DREX suffix in the absence of an EA
  * \172\ab	 - the register number from operand a in bits 7..4, with
- *                 the 4-bit immediate from operand b in bits 0..3.
+ *                 the 4-bit immediate from operand b in bits 3..0.
  * \173\xab	 - the register number from operand a in bits 7..4, with
- *		   the value b in bits 0..3.
+ *		   the value b in bits 3..0.
+ * \174\a	 - the register number from operand a in bits 7..4, and
+ *		   an arbitrary value in bits 3..0 (assembled as zero.)
  * \2ab          - a ModRM, calculated on EA in operand a, with the spare
  *                 field equal to digit b.
  * \250..\253    - same as \150..\153, except warn if the 64-bit operand
@@ -1006,6 +1008,7 @@ static int64_t calcsize(int32_t segment, int64_t offset, int bits,
 	    break;
 	case 0172:
 	case 0173:
+	case 0174:
 	    codes++;
 	    length++;
 	    break;
@@ -1611,6 +1614,14 @@ static void gencode(int32_t segment, int64_t offset, int bits,
 	    offset++;
 	    break;
 
+	case 0174:
+	    c = *codes++;
+	    opx = &ins->oprs[c];
+	    bytes[0] = nasm_regvals[opx->basereg] << 4;
+	    out(offset, segment, bytes, OUT_RAWDATA, 1, NO_SEG, NO_SEG);
+	    offset++;
+	    break;
+
         case 0250:
         case 0251:
         case 0252:
diff --git a/disasm.c b/disasm.c
index 378596a..c3ae541 100644
--- a/disasm.c
+++ b/disasm.c
@@ -656,6 +656,16 @@ static int matches(const struct itemplate *t, uint8_t *data,
 	}
 	break;
 
+	case 0174:
+	{
+	    uint8_t ximm = *data++;
+	    c = *r++;
+
+	    ins->oprs[c].basereg = ximm >> 4;
+	    ins->oprs[c].segment |= SEG_RMREG;
+	}
+	break;
+
 	case4(0200):
 	case4(0204):
 	case4(0210):
diff --git a/insns.pl b/insns.pl
index 5b45d7e..8199732 100644
--- a/insns.pl
+++ b/insns.pl
@@ -687,10 +687,14 @@ sub byte_code_compile($) {
 	    }
 	    $prefix_ok = 0;
 	} elsif ($op eq '/is4') {
-	    if (!defined($oppos{'i'} || !defined($oppos{'s'}))) {
-		die "$0: $line: $op without 'i' and 's' operands\n";
+	    if (!defined($oppos{'s'})) {
+		die "$0: $line: $op without 's' operand\n";
+	    }
+	    if (defined($oppos{'i'})) {
+		push(@codes, 0172, ($oppos{'s'} << 3)+$oppos{'i'});
+	    } else {
+		push(@codes, 0174, $oppos{'s'});
 	    }
-	    push(@codes, 0172, ($oppos{'s'} << 3)+$oppos{'i'});
 	    $prefix_ok = 0;
 	} elsif ($op =~ /^\/is4\=([0-9]+)$/) {
 	    my $imm = $1;
diff --git a/test/avx.asm b/test/avx.asm
index 018135b..11d3f1e 100644
--- a/test/avx.asm
+++ b/test/avx.asm
@@ -1,4 +1,14 @@
 		bits 64
+		vblendvpd	xmm2,xmm1,xmm0,xmm0
+		vblendvpd	xmm2,xmm1,xmm0
+		vblendvpd	ymm2,ymm1,ymm0,ymm0
+		vblendvpd	ymm2,ymm1,ymm0
+
+		vcvtsi2sd	xmm9,xmm10,ecx
+		vcvtsi2sd	xmm9,xmm10,rcx
+		vcvtsi2sd	xmm9,xmm10,dword [rdi]
+		vcvtsi2sd	xmm9,xmm10,qword [rdi] 
+
 		vpermil2ps	xmm0,xmm1,[rdi],xmm3,0
 		vpermil2ps	xmm0,xmm1,xmm2,[rdi],1
 		vpermil2ps	ymm0,ymm1,ymm2,ymm3,2