https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83535
Bug ID: 83535
Summary: Doesn’t respect Size for an object
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: ada
Assignee: unassigned at gcc dot gnu.org
Reporter: simon at pushface dot org
Target Milestone: ---
Created attachment 42946
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42946&action=edit
Demonstrator
The code in which this problem surfaced is for a Cortex-M CPU, and writes to
a hardware register to generate an external interrupt. The attached demo is
for the desktop.
I expected the write to NVIC_STIR to be a 32-bit write, with the input IRQ
extended to 32 bits (the hardware requires a 32-bit write). GCC 5, 6 and 7
all do this.
GCC 8 (8.0.0 20171216) only writes 8 bits, with the result that the
expected interrupt isn’t triggered.
The actual code is
procedure Trigger_Interrupt (IRQ : Ada.Interrupts.Interrupt_ID) is
-- The Software Trigger Interrupt Register.
NVIC_STIR : Ada.Interrupts.Interrupt_ID
with
Import,
Atomic,
Size => 32,
Address => System'To_Address (16#e000_ef00#);
begin
NVIC_STIR := IRQ;
end Trigger_Interrupt;
where
package Ada.Interrupts is
pragma Pure;
type Interrupt_ID is range 0 .. 44;
...
Discussion at
https://groups.google.com/d/msg/comp.lang.ada/ThIioaYg-_Y/OCWJNhX0DAAJ
