AVX-512: Add {evex} instruction prefix

For instructions that can be encoded either in VEX or EVEX,
{evex} forces nasm to encode in EVEX.

Signed-off-by: Jin Kyu Song <jin.kyu.song@intel.com>

4 files changed, 14 insertions, 0 deletions

diff --git a/assemble.c b/assemble.c
index e2e24c3b..100d131a 100644
--- a/assemble.c
+++ b/assemble.c
@@ -632,6 +632,9 @@ int64_t assemble(int32_t segment, int64_t offset, int bits, iflags_t cp,
                     case P_OSP:
                         c = 0x66;
                         break;
+                    case P_EVEX:
+                        /* EVEX */
+                        break;
                     case P_none:
                         break;
                     default:
@@ -786,6 +789,7 @@ int64_t insn_size(int32_t segment, int64_t offset, int bits, iflags_t cp,
                 break;
             case P_A64:
             case P_O64:
+            case P_EVEX:
             case P_none:
                 break;
             default:
@@ -2186,6 +2190,9 @@ static enum match_result matches(const struct itemplate *itemp,
                    nasm_regvals[instruction->oprs[i].basereg] >= 16 &&
                    !(itemp->flags & IF_AVX512)) {
             return MERR_ENCMISMATCH;
+        } else if (instruction->prefixes[PPS_EVEX] &&
+                   !(itemp->flags & IF_AVX512)) {
+            return MERR_ENCMISMATCH;
         }
     }
 
diff --git a/nasm.h b/nasm.h
index 5ca2aa58..34adc69b 100644
--- a/nasm.h
+++ b/nasm.h
@@ -553,6 +553,7 @@ enum prefixes { /* instruction prefixes */
     P_XACQUIRE,
     P_XRELEASE,
     P_BND,
+    P_EVEX,
     PREFIX_ENUM_LIMIT
 };
 
@@ -635,6 +636,7 @@ enum prefix_pos {
     PPS_SEG,    /* Segment override prefix */
     PPS_OSIZE,  /* Operand size prefix */
     PPS_ASIZE,  /* Address size prefix */
+    PPS_EVEX,   /* EVEX prefix */
     MAXPREFIX   /* Total number of prefix slots */
 };
 
diff --git a/parser.c b/parser.c
index e61d0a6f..700b4fc4 100644
--- a/parser.c
+++ b/parser.c
@@ -101,6 +101,8 @@ static int prefix_slot(int prefix)
     case P_A64:
     case P_ASP:
         return PPS_ASIZE;
+    case P_EVEX:
+        return PPS_EVEX;
     default:
         nasm_error(ERR_PANIC, "Invalid value %d passed to prefix_slot()", prefix);
         return -1;
diff --git a/tokens.dat b/tokens.dat
index 211eb099..284cf30a 100644
--- a/tokens.dat
+++ b/tokens.dat
@@ -122,3 +122,6 @@ rz-sae
 % TOKEN_DECORATOR, 0, TFLAG_BRC, BRC_*
 sae
 z
+
+% TOKEN_PREFIX, 0, TFLAG_BRC, P_*
+evex