Use __attribute__((interrupt)) for exception handler with GCC on STM32H7 Hello,I am wondering why the STmicro example code (STM32CubeH7) does not use the interrupt attribute for defining exception handlers.The difference I have noted when using this attribute is that it forces the stack alignement to 8 bytes:Example: void f(void);
void handler(void)
{
return f();
} compiles with arm-none-eabi-gcc 10.2.1 and -O1 -mthumb -mcpu=cortex-m7 in: handler():
push {r3, lr}
bl f()
pop {r3, pc} whereas if I add the attribute "interrupt": handler():
mov r0, sp
bic r1, r0, #7
mov sp, r1
push {r0, lr}
bl f()
pop {r0, lr}
mov sp, r0
bx lr One can see the difference is in the 3 first instructions that align the stack to 8 bytes. Indeed the stack is not always aligned to 8 bytes inside a function. From the Procedure Call Standard: 6.2.1.1 Universal stack constraints
At all times the following basic constraints must hold:
Stack-limit ≤ SP ≤ stack-base. The stack pointer must lie within the extent of t
