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| author | gjl <gjl@138bc75d-0d04-0410-961f-82ee72b054a4> | 2016-10-24 11:02:51 +0000 |
|---|---|---|
| committer | gjl <gjl@138bc75d-0d04-0410-961f-82ee72b054a4> | 2016-10-24 11:02:51 +0000 |
| commit | 2cd66116afe4a74474f7b628c9cd17fee50c8453 (patch) | |
| tree | b7c4975fab294b75e604f23f0d4cc6a39addca46 /gcc/doc | |
| parent | dfa8b1b6ed3f68c4c6e6736180a0cf620900fb7e (diff) | |
| download | gcc-2cd66116afe4a74474f7b628c9cd17fee50c8453.tar.gz | |
gcc/
PR target/78093
* doc/extend.texi (AVR Variable Attributes) [absdata]: Document it.
* config/avr/avr.c (AVR_SYMBOL_FLAG_TINY_ABSDATA): New macro.
(avr_address_tiny_absdata_p): New static function.
(avr_legitimate_address_p, avr_legitimize_address) [AVR_TINY]: Use
it to determine validity of constant addresses.
(avr_attribute_table) [absdata]: New variable attribute...
(avr_handle_absdata_attribute): ...and handler.
(avr_decl_absdata_p): New static function.
(avr_encode_section_info) [AVR_TINY]: Use it to add flag
AVR_SYMBOL_FLAG_TINY_ABSDATA to respective symbols_refs.
(avr_address_cost) [AVR_TINY]: absdata addresses cost 2.
gcc/testsuite/
PR target/78093
* lib/target-supports.exp (check_effective_target_avr_tiny): New proc.
* gcc.target/avr/torture/tiny-absdata-1.c: New test.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@241468 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/doc')
| -rw-r--r-- | gcc/doc/extend.texi | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index 62a5f2963db..0669f7999be 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -5973,6 +5973,33 @@ memory-mapped peripherals that may lie outside the io address range. volatile int porta __attribute__((address (0x600))); @end smallexample +@item absdata +@cindex @code{absdata} variable attribute, AVR +Variables in static storage and with the @code{absdata} attribute can +be accessed by the @code{LDS} and @code{STS} instructions which take +absolute addresses. + +@itemize @bullet +@item +This attribute is only supported for the reduced AVR Tiny core +like ATtiny40. + +@item +You must make sure that respective data is located in the +address range @code{0x40}@dots{}@code{0xbf} accessible by +@code{LDS} and @code{STS}. One way to achieve this as an +appropriate linker description file. + +@item +If the location does not fit the address range of @code{LDS} +and @code{STS}, there is currently (Binutils 2.26) just an unspecific +warning like +@quotation +@code{module.c:(.text+0x1c): warning: internal error: out of range error} +@end quotation + +@end itemize + @end table @node Blackfin Variable Attributes |