examples/natmod/deflate: Fix build for Xtensa.

agatti · dpgeorge · commit 887125fc589d · 2025-06-04T22:35:39.000+10:00
This commit provides the appropriate external symbol addresses to let
the "deflate" example natmod build for the Xtensa platform.

Unlike other natmods that require an external symbol list to build
without bringing in the whole runtime libraries set, this natmod is
referencing the `__modsi3` symbol which was removed from the ESP8266's
SDK but not present in ROM.  The latter only has a `__umodsi3`
implementation that only operates on unsigned values, and thus unable to
handle this natmod.  Thus, the extended library resolution process is
enabled for this natmod as a `__modsi3` implementation is made available
that way (still using ROM symbols whenever possible).  This also means
that symbols that appear in both ROM and external libraries sort of
co-exist in the final MPY file, with ROM symbols being used by natmod
code but the implementation from the library still exists in the final
MPY file, unused.

Signed-off-by: Alessandro Gatti &lt;a.gatti@frob.it&gt;
diff --git a/examples/natmod/deflate/Makefile b/examples/natmod/deflate/Makefile
@@ -8,6 +8,12 @@ MOD = deflate_$(ARCH)
 SRC = deflate.c
 
 # Architecture to build for (x86, x64, armv7m, xtensa, xtensawin, rv32imc)
-ARCH = x64
+ARCH ?= x64
+
+ifeq ($(ARCH),xtensa)
+# Link with libm.a and libgcc.a from the toolchain
+LINK_RUNTIME = 1
+MPY_EXTERN_SYM_FILE=$(MPY_DIR)/ports/esp8266/boards/eagle.rom.addr.v6.ld
+endif
 
 include $(MPY_DIR)/py/dynruntime.mk
