[avr-libc-dev] [bug #27434] Arguments of macros must be protected in parentheses

[Shaun Jackman]

URL:
  <http://savannah.nongnu.org/bugs/?27434>

                 Summary: Arguments of macros must be protected in
parentheses
                 Project: AVR C Runtime Library
            Submitted by: sjackman
            Submitted on: Sun 13 Sep 2009 06:58:38 PM GMT
                Category: Header
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Header files
                  Status: None
        Percent Complete: 0%
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 1.6.7
           Fixed Release: None

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Details:

I noticed this bug with boot_page_fill, but it applies to pretty much every
asm macro and macros in general. Macro arguments must be protected in
parentheses. These two lines

          "z" ((uint16_t)address),               \
          "r" ((uint16_t)data)                   \

should be

          "z" ((uint16_t)(address)),               \
          "r" ((uint16_t)(data))                   \

otherwise the following code will break because the cast operation has higher
precedence than the shift operation:

uint32_t u32 = 123456789;
boot_page_fill(0, u32 >> 16);

Fortunately, gcc gives a warning in this case.

Cheers,
Shaun




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