Compiler Support
[Utility Library]
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Bit Operations | |
These functions are not meant to be called directly. Please see Bit Operations instead. | |
| static int_fast8_t | compiler_priv_ctz8 (uint8_t x) |
| static int_fast8_t | compiler_priv_ctz16 (uint16_t x) |
| static int_fast8_t | compiler_priv_ctz32 (uint32_t x) |
| static int_fast8_t | compiler_priv_clz8 (uint8_t x) |
| static int_fast8_t | compiler_priv_clz16 (uint16_t x) |
| static int_fast8_t | compiler_priv_clz32 (uint32_t x) |
| static uint8_t | compiler_priv_brev8 (uint8_t x) |
| static uint16_t | compiler_priv_brev16 (uint16_t x) |
| static uint32_t | compiler_priv_brev32 (uint32_t x) |
| static int8_t | compiler_min_s8 (int8_t a, int8_t b) |
| static int16_t | compiler_min_s16 (int16_t a, int16_t b) |
| static int32_t | compiler_min_s32 (int32_t a, int32_t b) |
| static int64_t | compiler_min_s64 (int64_t a, int64_t b) |
| static uint8_t | compiler_min_u8 (uint8_t a, uint8_t b) |
| static uint16_t | compiler_min_u16 (uint16_t a, uint16_t b) |
| static uint32_t | compiler_min_u32 (uint32_t a, uint32_t b) |
| static uint64_t | compiler_min_u64 (uint64_t a, uint64_t b) |
| static int8_t | compiler_max_s8 (int8_t a, int8_t b) |
| static int16_t | compiler_max_s16 (int16_t a, int16_t b) |
| static int32_t | compiler_max_s32 (int32_t a, int32_t b) |
| static int64_t | compiler_max_s64 (int64_t a, int64_t b) |
| static uint8_t | compiler_max_u8 (uint8_t a, uint8_t b) |
| static uint16_t | compiler_max_u16 (uint16_t a, uint16_t b) |
| static uint32_t | compiler_max_u32 (uint32_t a, uint32_t b) |
| static uint64_t | compiler_max_u64 (uint64_t a, uint64_t b) |
| #define | compiler_ctz(x) compiler_priv_demux_size(sizeof(x), compiler_priv_ctz, (x)) |
| Count Trailing Zeroes. | |
| #define | compiler_clz(x) compiler_priv_demux_size(sizeof(x), compiler_priv_clz, (x)) |
| Count Leading Zeroes. | |
| #define | compiler_brev(x) compiler_priv_demux_size(sizeof(x), compiler_priv_brev, (x)) |
| Reverse the order of the bits in x. | |
Extended type checking | |
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| #define | __bitwise __attribute__((bitwise)) |
| Make a type incompatible with all other types. | |
| #define | __virtual |
| Mark a pointer as virtual. | |
| #define | __physical __attribute__((noderef, address_space(1))) |
| Mark a pointer as physical. | |
| #define | __force __attribute__((force)) |
| Force a type cast. | |
Function and Data Attributes | |
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| #define | __noreturn |
| The function does not return. | |
| #define | __must_check |
| The return value must be checked. | |
| #define | __used |
| Mark a function or data object as being used. | |
| #define | __always_inline inline __attribute__((always_inline)) |
| The function should always be inlined. | |
| #define | __nonnull(...) |
| Define non-null function attributes. | |
| #define | __printf_format(fmt_index, first_arg_index) |
| The function takes a printf-like format string. | |
| #define | compiler_align_data(byte_alignment) |
| Align data variables to a give byte value. | |
Optimization Control | |
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| #define | likely(exp) (exp) |
| The expression exp is likely to be true. | |
| #define | unlikely(exp) (exp) |
| The expression exp is unlikely to be true. | |
| #define | barrier() do { } while (0) |
| Optimization barrier. | |
| #define | is_constant(exp) (0) |
| Determine if an expression evaluates to a constant value. | |
Top-level Directives | |
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| #define | COMPILER_PRAGMA(arg) _Pragma(#arg) |
| Emit the compiler pragma arg. | |
| #define | COMPILER_PACK_SET(alignment) COMPILER_PRAGMA(pack(alignment)) |
| Set maximum alignment for subsequent struct and union definitions to alignment. | |
| #define | COMPILER_PACK_RESET() COMPILER_PRAGMA(pack()) |
| Set default alignment for subsequent struct and union definitions. | |
| #define | ERROR_FUNC(name, msg) extern int name(void) |
| Fail compilation if function call isn't eliminated. | |
Interrupt Control | |
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| #define | cpu_irq_enable() asm volatile("sei" ::: "memory") |
| Enable interrupts globally. | |
| #define | cpu_irq_disable() asm volatile("cli" ::: "memory") |
| Disable interrupts globally. | |
Detailed Description
This group provides various mechanisms which are not defined by the C standard, but supported by most compilers anyway. Each compiler typically defines its own set of extensions for providing these mechanisms, so we need a common abstraction layer to use them in applications and drivers.
Define Documentation
| #define __always_inline inline __attribute__((always_inline)) |
The function should always be inlined.
This annotation instructs the compiler to ignore its inlining heuristics and inline the function no matter how big it thinks it becomes.
| #define __bitwise __attribute__((bitwise)) |
Make a type incompatible with all other types.
This is a sparse attribute which has no effect on other compilers. Declaring a type as __bitwise will cause sparse to complain if it is implicitly or explicitly cast to a different type. This is useful when dealing with foreign-endian types, for example, since it is always a bug if they are accessed without proper byte swapping.
| #define __force __attribute__((force)) |
Force a type cast.
This modifier can be used to silence any warnings from sparse with regards to casting of bitwise types or casting from one address space to another. This is typically used by the functions that provides the mappings between those types, e.g. byte swapping functions.
Referenced by be16_to_cpu(), be32_to_cpu(), cpu_to_be16(), cpu_to_be32(), cpu_to_le16(), cpu_to_le32(), le16_to_cpu(), and le32_to_cpu().
| #define __must_check |
The return value must be checked.
This annotation may cause the compiler to warn if someone calls the annotated function without checking its return value.
Definition at line 145 of file compiler.h.
| #define __nonnull | ( | ... | ) |
Define non-null function attributes.
This function attribute specifies that some function parameters must be non-null pointers.
Definition at line 182 of file compiler.h.
| #define __noreturn |
The function does not return.
This function annotation gives a hint to the compiler that the function being annotated does not return. This may give the compiler some more room for optimizations.
Definition at line 134 of file compiler.h.
| #define __physical __attribute__((noderef, address_space(1))) |
Mark a pointer as physical.
A pointer marked with this annotation cannot be dereferenced since it belongs to an address space which cannot be accessed directly on all platforms. It must be mapped to a virtual address by calling an appropriate mapping function.
| #define __printf_format | ( | fmt_index, | |||
| first_arg_index | ) |
The function takes a printf-like format string.
This annotation may cause the compiler to emit a warning if the format string doesn't match the parameters given.
Definition at line 193 of file compiler.h.
| #define __used |
Mark a function or data object as being used.
The compiler will normally warn about functions or variables defined as static but not referenced anywhere. By annotating them with __used, the compiler will shut up and emit the symbol. This is useful when a symbol is only referenced by inline assembly code, for example.
Definition at line 159 of file compiler.h.
| #define __virtual |
Mark a pointer as virtual.
This annotation does nothing on any compiler, since the virtual address space is the default one.
| #define barrier | ( | ) | do { } while (0) |
Optimization barrier.
This macro forces the compiler to reload any variables from memory. Local variables are left alone, unless they had their address taken at some point.
Definition at line 246 of file compiler.h.
Referenced by atomic_read(), atomic_write(), cpu_irq_restore(), ring_extract_entries(), and ring_insert_entries().
| #define compiler_align_data | ( | byte_alignment | ) |
Align data variables to a give byte value.
- Parameters:
-
byte_alignment Data alignment given in bytes
This function will align a data variable in memory to the supplied number of bytes. The number of bytes must be a power of two, e.g., 1, 2, 4, 8, 16, etc.
The compiler_align_data attribute must be placed at the very beginning of the declaration of the variable.
- Example:
- compiler_align_data(4) static uint32_t dma_buffer[64];
Definition at line 213 of file compiler.h.
| #define compiler_brev | ( | x | ) | compiler_priv_demux_size(sizeof(x), compiler_priv_brev, (x)) |
Reverse the order of the bits in x.
- See also:
- bit_word_reverse()
Definition at line 480 of file compiler.h.
| #define compiler_clz | ( | x | ) | compiler_priv_demux_size(sizeof(x), compiler_priv_clz, (x)) |
Count Leading Zeroes.
- See also:
- bit_word_find_last_one_bit()
Definition at line 428 of file compiler.h.
Referenced by ilog2().
| #define compiler_ctz | ( | x | ) | compiler_priv_demux_size(sizeof(x), compiler_priv_ctz, (x)) |
Count Trailing Zeroes.
- See also:
- bit_word_find_first_one_bit()
Definition at line 374 of file compiler.h.
| #define COMPILER_PACK_RESET | ( | ) | COMPILER_PRAGMA(pack()) |
Set default alignment for subsequent struct and union definitions.
Definition at line 290 of file compiler.h.
| #define COMPILER_PACK_SET | ( | alignment | ) | COMPILER_PRAGMA(pack(alignment)) |
Set maximum alignment for subsequent struct and union definitions to alignment.
Definition at line 281 of file compiler.h.
| #define COMPILER_PRAGMA | ( | arg | ) | _Pragma(#arg) |
Emit the compiler pragma arg.
- Parameters:
-
arg The pragma directive as it would appear after #pragma (i.e. not stringified).
Definition at line 273 of file compiler.h.
| #define cpu_irq_disable | ( | ) | asm volatile("cli" ::: "memory") |
Disable interrupts globally.
This implies a barrier to ensure that memory operations don't "leak" out of the critical section.
Definition at line 41 of file compiler-gcc.h.
Referenced by cpu_irq_save().
| #define cpu_irq_enable | ( | ) | asm volatile("sei" ::: "memory") |
Enable interrupts globally.
This implies a barrier to ensure that memory operations don't "leak" out of the critical section.
Definition at line 42 of file compiler-gcc.h.
Referenced by cpu_enter_sleep().
| #define ERROR_FUNC | ( | name, | |||
| msg | ) | extern int name(void) |
Fail compilation if function call isn't eliminated.
If the compiler fails to optimize away all calls to the function name, terminate compilation and display msg to the user.
Note that not all compilers support this, so this is best-effort only. Sometimes, there may be a linker error instead, and when optimization is disabled, this mechanism will be completely disabled.
Definition at line 305 of file compiler.h.
| #define is_constant | ( | exp | ) | (0) |
Determine if an expression evaluates to a constant value.
- Parameters:
-
exp Any expression
- Returns:
- true if exp is constant, false otherwise.
Definition at line 259 of file compiler.h.
Referenced by gpio_get_value(), gpio_set_value(), and ilog2().
| #define likely | ( | exp | ) | (exp) |
The expression exp is likely to be true.
Definition at line 226 of file compiler.h.
| #define unlikely | ( | exp | ) | (exp) |
The expression exp is unlikely to be true.
Definition at line 234 of file compiler.h.
