1 files changed, 14 insertions, 8 deletions

diff --git a/src/lj_arch.h b/src/lj_arch.h
index 17b766f8..03da79a6 100644
--- a/src/lj_arch.h
+++ b/src/lj_arch.h
@@ -95,6 +95,11 @@
 #define LJ_TARGET_POSIX         (LUAJIT_OS > LUAJIT_OS_WINDOWS)
 #define LJ_TARGET_DLOPEN        LJ_TARGET_POSIX
 
+#define LJ_NUMMODE_SINGLE       0       /* Single-number mode only. */
+#define LJ_NUMMODE_SINGLE_DUAL  1       /* Default to single-number mode. */
+#define LJ_NUMMODE_DUAL         2       /* Dual-number mode only. */
+#define LJ_NUMMODE_DUAL_SINGLE  3       /* Default to dual-number mode. */
+
 /* Set target architecture properties. */
 #if LUAJIT_TARGET == LUAJIT_ARCH_X86
 
@@ -108,7 +113,7 @@
 #define LJ_TARGET_EHRETREG      0
 #define LJ_TARGET_MASKSHIFT     1
 #define LJ_TARGET_MASKROT       1
-#define LJ_ARCH_DUALNUM         1
+#define LJ_ARCH_NUMMODE         LJ_NUMMODE_SINGLE_DUAL
 
 #elif LUAJIT_TARGET == LUAJIT_ARCH_X64
 
@@ -123,7 +128,7 @@
 #define LJ_TARGET_JUMPRANGE     31      /* +-2^31 = +-2GB */
 #define LJ_TARGET_MASKSHIFT     1
 #define LJ_TARGET_MASKROT       1
-#define LJ_ARCH_DUALNUM         1
+#define LJ_ARCH_NUMMODE         LJ_NUMMODE_SINGLE_DUAL
 
 #elif LUAJIT_TARGET == LUAJIT_ARCH_ARM
 
@@ -139,7 +144,7 @@
 #define LJ_TARGET_MASKSHIFT     0
 #define LJ_TARGET_MASKROT       1
 #define LJ_TARGET_UNIFYROT      2       /* Want only IR_BROR. */
-#define LJ_ARCH_DUALNUM         2
+#define LJ_ARCH_NUMMODE         LJ_NUMMODE_DUAL
 #if LJ_TARGET_OSX
 /* Runtime code generation is restricted on iOS. Complain to Apple, not me. */
 #define LJ_ARCH_NOJIT           1
@@ -157,7 +162,7 @@
 #define LJ_TARGET_MASKSHIFT     0
 #define LJ_TARGET_MASKROT       1
 #define LJ_TARGET_UNIFYROT      1       /* Want only IR_BROL. */
-#define LJ_ARCH_DUALNUM         1
+#define LJ_ARCH_NUMMODE         LJ_NUMMODE_SINGLE       /* NYI: dual-num. */
 #define LJ_ARCH_NOFFI           1       /* NYI: comparisons, calls. */
 #define LJ_ARCH_NOJIT           1
 
@@ -177,7 +182,7 @@
 #define LJ_TARGET_MASKSHIFT     0
 #define LJ_TARGET_MASKROT       1
 #define LJ_TARGET_UNIFYROT      1       /* Want only IR_BROL. */
-#define LJ_ARCH_DUALNUM         0
+#define LJ_ARCH_NUMMODE         LJ_NUMMODE_SINGLE
 #define LJ_ARCH_NOFFI           1       /* NYI: comparisons, calls. */
 #define LJ_ARCH_NOJIT           1
 
@@ -232,9 +237,10 @@
 #endif
 #endif
 
-/* Enable or disable the dual-number VM. */
-#if LJ_ARCH_DUALNUM == 2 || \
-    (defined(LUAJIT_ENABLE_DUALNUM) && LJ_ARCH_DUALNUM == 1)
+/* Enable or disable the dual-number mode for the VM. */
+#if LJ_ARCH_NUMMODE == LJ_NUMMODE_DUAL || \
+    (LJ_ARCH_NUMMODE == LJ_NUMMODE_DUAL_SINGLE && LUAJIT_NUMMODE != 1) || \
+    (LJ_ARCH_NUMMODE == LJ_NUMMODE_SINGLE_DUAL && LUAJIT_NUMMODE == 2)
 #define LJ_DUALNUM              1
 #else
 #define LJ_DUALNUM              0