With this change, it is possible to fully use CGo on ESP32/ESP8266
chips. The following will work:
tinygo flash -target=d1mini -port=/dev/ttyUSB0 ./testdata/cgo/
tinygo flash -target=esp32-mini32 -port=/dev/ttyUSB0 ./testdata/cgo/
Previously it would produce output like the following:
/tmp/tinygo905539688/main.o:(.literal.runtime.run$1$gowrapper+0x150): undefined reference to `strcpy'
/tmp/tinygo905539688/main.o:(.literal.runtime.run$1$gowrapper+0x154): undefined reference to `strlen'
With this change, it is possible to compile ./testdata/float.go for the
ESP8266 and run it successfully. Previously it would result in many
linker error like this:
/tmp/tinygo494494333/main.o:(.literal.runtime.printfloat64+0x0): undefined reference to `__unorddf2'
/tmp/tinygo494494333/main.o:(.literal.runtime.printfloat64+0x4): undefined reference to `__gtdf2'
/tmp/tinygo494494333/main.o:(.literal.runtime.printfloat64+0xc): undefined reference to `__nedf2'
/tmp/tinygo494494333/main.o:(.literal.runtime.printfloat64+0x10): undefined reference to `__ltdf2'
/tmp/tinygo494494333/main.o:(.literal.runtime.printfloat64+0x1c): undefined reference to `__gedf2'
I have verified that the output on the serial console matches
./testdata/float.txt when run on the ESP8266.
I have chosed to call this implementation `esp8266` instead of `xtensa`
as it has been written specifically for the ESP8266 and there are no
other Xtensa chips with the CALL0 ABI (no windowing) that I know of. The
only other related chip is the ESP32, which does implement register
windowing and thus needs a very different implementation.
Ayke van Laethem