Serial Print Float / Double

[oclyke]

Subject of the issue

Serial print functions cause a hard fault when handling float/double precision variables.

Your workbench

• master branch @8628c31
• Artemis boards

Steps to reproduce

void setup() {
  Serial.begin(9600);

  Serial.println("Float / Double print failure");
  delay(100); // allow banner to print before crash

  Serial.println(10); // print(int) works

  Serial.println(1000.0/960); // print(float/double) crashes into a HardFault

  Serial.println("I should be displayed but instead there is a crash");
}

void loop() {
  // put your main code here, to run repeatedly:

}

Expected behaviour

Serial output should read:

Float / Double print failure
10
1.04
I should be displayed but instead there is a crash

Actual behaviour

Serial output actually shows:

Float / Double print failure
10

[oclyke]

This issue could be exhibited in releases 1.0.24, 1.0.25, and 1.0.26 because they relied on the 7-2017q4 release of gcc packaged by Arduino. This issue is currently not applicable. I will re-open if a future version needs to use that toolchain