mpy-cross: Enable Xtensa-Windowed native emitter.

Selectable via the command line: -march=xtensawin.

mpy-cross/main.c

@@ -109,7 +109,7 @@ STATIC int usage(char **argv) {
 "-msmall-int-bits=number : set the maximum bits used to encode a small-int\n"
 "-mno-unicode : don't support unicode in compiled strings\n"
 "-mcache-lookup-bc : cache map lookups in the bytecode\n"
-"-march=<arch> : set architecture for native emitter; x86, x64, armv6, armv7m, xtensa\n"
+"-march=<arch> : set architecture for native emitter; x86, x64, armv6, armv7m, xtensa, xtensawin\n"
 "\n"
 "Implementation specific options:\n", argv[0]
 );
@@ -288,6 +288,9 @@ MP_NOINLINE int main_(int argc, char **argv) {
                 } else if (strcmp(arch, "xtensa") == 0) {
                     mp_dynamic_compiler.native_arch = MP_NATIVE_ARCH_XTENSA;
                     mp_dynamic_compiler.nlr_buf_num_regs = MICROPY_NLR_NUM_REGS_XTENSA;
+                } else if (strcmp(arch, "xtensawin") == 0) {
+                    mp_dynamic_compiler.native_arch = MP_NATIVE_ARCH_XTENSAWIN;
+                    mp_dynamic_compiler.nlr_buf_num_regs = MICROPY_NLR_NUM_REGS_XTENSAWIN;
                 } else {
                     return usage(argv);
                 }

mpy-cross/mpconfigport.h

@@ -39,6 +39,7 @@
 #define MICROPY_EMIT_ARM            (1)
 #define MICROPY_EMIT_XTENSA         (1)
 #define MICROPY_EMIT_INLINE_XTENSA  (1)
+#define MICROPY_EMIT_XTENSAWIN      (1)
 
 #define MICROPY_DYNAMIC_COMPILER    (1)
 #define MICROPY_COMP_CONST_FOLDING  (1)