+# define VISIBLE16 __VISIBLE
+// Notes a function as externally visible in the 32bit flat code chunk.
+# define VISIBLE32FLAT __section(".discard.func32flat." UNIQSEC) noinline
+// Notes a 32bit flat function that will only be called during init.
+# define VISIBLE32INIT VISIBLE32FLAT
+// Notes a function as externally visible in the 32bit segmented code chunk.
+# define VISIBLE32SEG __section(".discard.func32seg." UNIQSEC) noinline
+// Designate a variable as (only) visible to 16bit code.
+# define VAR16 __section(".data16." UNIQSEC)
+// Designate a variable as visible to 16bit, 32bit, and assembler code.
+# define VAR16VISIBLE VAR16 __VISIBLE
+// Designate a variable as externally visible (in addition to all internal code).
+# define VAR16EXPORT __section(".data16.export." UNIQSEC) __VISIBLE
+// Designate a variable at a specific 16bit address
+# define VAR16FIXED(addr) __aligned(1) __VISIBLE __section(".fixedaddr." __stringify(addr))
+// Designate a variable as (only) visible to 32bit segmented code.
+# define VAR32SEG __section(".discard.var32seg." UNIQSEC)
+// Designate a 32bit variable also available in 16bit "big real" mode.
+# define VAR32FLATVISIBLE __section(".discard.var32flat." UNIQSEC) __VISIBLE __weak
+// Designate top-level assembler as 16bit only.
+# define ASM16(code) __ASM(code)
+// Designate top-level assembler as 32bit flat only.
+# define ASM32FLAT(code)
+// Compile time check for a given mode.
+# define ASSERT16() do { } while (0)
+# define ASSERT32SEG() __force_link_error__only_in_32bit_segmented()
+# define ASSERT32FLAT() __force_link_error__only_in_32bit_flat()
+#elif MODESEGMENT == 1
+# define VISIBLE16 __section(".discard.func16." UNIQSEC) noinline
+# define VISIBLE32FLAT __section(".discard.func32flat." UNIQSEC) noinline
+# define VISIBLE32INIT VISIBLE32FLAT
+# define VISIBLE32SEG __VISIBLE
+# define VAR16 __section(".discard.var16." UNIQSEC)
+# define VAR16VISIBLE VAR16 __VISIBLE __weak
+# define VAR16EXPORT VAR16VISIBLE
+# define VAR16FIXED(addr) VAR16VISIBLE
+# define VAR32SEG __section(".data32seg." UNIQSEC)
+# define VAR32FLATVISIBLE __section(".discard.var32flat." UNIQSEC) __VISIBLE __weak
+# define ASM16(code)
+# define ASM32FLAT(code)
+# define ASSERT16() __force_link_error__only_in_16bit()
+# define ASSERT32SEG() do { } while (0)
+# define ASSERT32FLAT() __force_link_error__only_in_32bit_flat()