f29e6f9020
Overflows in conversions from floating-point to integer are undefined behavior in the C99 standard. (Clause 6.3.1.4: "If the value of the integral part cannot be represented by the integer type, the behavior is undefined.") When UBSAN is enabled, this gets reported at `srand()` calls. (The random seed is usually initialized using the date port API, which represents dates as `double`s. But `srand` takes an `unsigned int`. A simple cast from `double` to `unsigned` becomes undefined behavior if the value is too large. And "now" is too large nowadays. So, effectively, all executions start with an undefined behavior.) This patch fixes this by casting the floating-point value of the date to an integer through a union. JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu
About
Files in this folder (targets/esp8266) are copied from
examples/project_template of esp_iot_rtos_sdk and modified for JerryScript.
You can view online from
this page.
How to build JerryScript for ESP8266
1. SDK
Follow this page to setup build environment
2. Building JerryScript
# assume you are in jerryscript folder
make -f ./targets/esp8266/Makefile.esp8266
Output files should be placed at $BIN_PATH
3. Flashing for ESP8266 12E
Follow this page to get details about this board.
make -f ./targets/esp8266/Makefile.esp8266 flash
Default USB device is /dev/ttyUSB0. If you have different one, give with USBDEVICE, like;
USBDEVICE=/dev/ttyUSB1 make -f ./targets/esp8266/Makefile.esp8266 flash
4. Running
- power off
- connect GPIO2 with serial of 470 Ohm + LED and to GND
- power On
LED should blink on and off every second
5. Cleaning
To clean the build result:
make -f ./targets/esp8266/Makefile.esp8266 clean
To clean the board's flash memory:
make -f ./targets/esp8266/Makefile.esp8266 erase_flash
6. Optimizing initial RAM usage (ESP8266 specific)
The existing open source gcc compiler with Xtensa support stores const(ants) in the same limited RAM where our code needs to run.
It is possible to force the compiler to store a constant into ROM and also read it from there thus saving RAM.
The only requirement is to add JERRY_ATTR_CONST_DATA attribute to your constant.
For example:
static const lit_magic_size_t lit_magic_string_sizes[] =
can be modified to
static const lit_magic_size_t lit_magic_string_sizes[] JERRY_ATTR_CONST_DATA =
That is already done to some constants in jerry-core. E.g.:
- vm_decode_table
- ecma_property_hashmap_steps
- lit_magic_string_sizes
- unicode_letter_interv_sps
- unicode_letter_interv_len
- unicode_non_letter_ident_
- unicode_letter_chars