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| author | Georg-Johann Lay <avr@gjlay.de> | 2024-07-19 18:22:26 +0200 |
|---|---|---|
| committer | Georg-Johann Lay <avr@gjlay.de> | 2024-07-19 18:24:35 +0200 |
| commit | 9116490c1b03dac18f10e42df03731a3aed0b4e9 (patch) | |
| tree | c34aeb3c3e1f3dfd743fd1b0cdb1f0048ebc7222 /gcc/doc | |
| parent | 8d6994f33a98a168151a57a3d21395b19196cd9d (diff) | |
| download | gcc-9116490c1b03dac18f10e42df03731a3aed0b4e9.zip gcc-9116490c1b03dac18f10e42df03731a3aed0b4e9.tar.gz gcc-9116490c1b03dac18f10e42df03731a3aed0b4e9.tar.bz2 | |
AVR: Support new built-in function __builtin_avr_mask1.
gcc/
* config/avr/builtins.def (MASK1): New DEF_BUILTIN.
* config/avr/avr.cc (avr_rtx_costs_1): Handle rtx costs for
expressions like __builtin_avr_mask1.
(avr_init_builtins) <uintQI_ftype_uintQI_uintQI>: New tree type.
(avr_expand_builtin) [AVR_BUILTIN_MASK1]: Diagnose unexpected forms.
(avr_fold_builtin) [AVR_BUILTIN_MASK1]: Handle case.
* config/avr/avr.md (gen_mask1): New expand helper.
(mask1_0x01_split, mask1_0x80_split, mask1_0xfe_split): New
insn-and-split.
(*mask1_0x01, *mask1_0x80, *mask1_0xfe): New insns.
* doc/extend.texi (AVR Built-in Functions) <__builtin_avr_mask1>:
Document new built-in function.
gcc/testsuite/
* gcc.target/avr/torture/builtin-mask1.c: New test.
Diffstat (limited to 'gcc/doc')
| -rw-r--r-- | gcc/doc/extend.texi | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index 0b572af..4b77599 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -16974,6 +16974,23 @@ __builtin_avr_insert_bits (0x01234567, bits, 0); @end smallexample @enddefbuiltin +@defbuiltin{uint8_t __builtin_avr_mask1 (uint8_t @var{mask}, uint8_t @var{offs})} +Rotate the 8-bit constant value @var{mask} by an offset of @var{offs}, +where @var{mask} is in @{ 0x01, 0xfe, 0x7f, 0x80 @}. +This built-in can be use as an alternative to 8-bit expressions like +@code{1 << offs} when their computation consumes too much +time, and @var{offs} is known to be in the range 0@dots{}7. +@example +__builtin_avr_mask1 (1, offs) // same like 1 << offs +__builtin_avr_mask1 (~1, offs) // same like ~(1 << offs) +__builtin_avr_mask1 (0x80, offs) // same like 0x80 >> offs +__builtin_avr_mask1 (~0x80, offs) // same like ~(0x80 >> offs) +@end example +The open coded C versions take at least @code{5 + 4 * @var{offs}} cycles +(and 5 instructions), whereas the built-in takes 7 cycles and instructions +(8 cycles and instructions in the case of @code{@var{mask} = 0x7f}). +@enddefbuiltin + @defbuiltin{void __builtin_avr_nops (uint16_t @var{count})} Insert @var{count} @code{NOP} instructions. The number of instructions must be a compile-time integer constant. |