Commit 74360f14 by Georg-Johann Lay Committed by Georg-Johann Lay

invoke.texi (AVR Built-in Functions): Re-layout section.

gcc/
	* doc/invoke.texi (AVR Built-in Functions): Re-layout section.

From-SVN: r250419
parent ba61fc53
2017-07-21 Georg-Johann Lay <avr@gjlay.de>
* doc/invoke.texi (AVR Built-in Functions): Re-layout section.
2016-07-21 Jan Hubicka <hubicka@ucw.cz>
* cfgcleanup.c (flow_find_cross_jump): Do not crossjump across
......
......@@ -12748,54 +12748,37 @@ or if not a specific built-in is implemented or not. For example, if
@code{__builtin_avr_nop} is available the macro
@code{__BUILTIN_AVR_NOP} is defined to @code{1} and undefined otherwise.
The following built-in functions map to the respective machine
@table @code
@item void __builtin_avr_nop (void)
@itemx void __builtin_avr_sei (void)
@itemx void __builtin_avr_cli (void)
@itemx void __builtin_avr_sleep (void)
@itemx void __builtin_avr_wdr (void)
@itemx unsigned char __builtin_avr_swap (unsigned char)
@itemx unsigned int __builtin_avr_fmul (unsigned char, unsigned char)
@itemx int __builtin_avr_fmuls (char, char)
@itemx int __builtin_avr_fmulsu (char, unsigned char)
These built-in functions map to the respective machine
instruction, i.e.@: @code{nop}, @code{sei}, @code{cli}, @code{sleep},
@code{wdr}, @code{swap}, @code{fmul}, @code{fmuls}
resp. @code{fmulsu}. The three @code{fmul*} built-ins are implemented
as library call if no hardware multiplier is available.
@smallexample
void __builtin_avr_nop (void)
void __builtin_avr_sei (void)
void __builtin_avr_cli (void)
void __builtin_avr_sleep (void)
void __builtin_avr_wdr (void)
unsigned char __builtin_avr_swap (unsigned char)
unsigned int __builtin_avr_fmul (unsigned char, unsigned char)
int __builtin_avr_fmuls (char, char)
int __builtin_avr_fmulsu (char, unsigned char)
@end smallexample
In order to delay execution for a specific number of cycles, GCC
implements
@smallexample
void __builtin_avr_delay_cycles (unsigned long ticks)
@end smallexample
@noindent
@code{ticks} is the number of ticks to delay execution. Note that this
@item void __builtin_avr_delay_cycles (unsigned long ticks)
Delay execution for @var{ticks} cycles. Note that this
built-in does not take into account the effect of interrupts that
might increase delay time. @code{ticks} must be a compile-time
might increase delay time. @var{ticks} must be a compile-time
integer constant; delays with a variable number of cycles are not supported.
@smallexample
char __builtin_avr_flash_segment (const __memx void*)
@end smallexample
@noindent
@item char __builtin_avr_flash_segment (const __memx void*)
This built-in takes a byte address to the 24-bit
@ref{AVR Named Address Spaces,address space} @code{__memx} and returns
the number of the flash segment (the 64 KiB chunk) where the address
points to. Counting starts at @code{0}.
If the address does not point to flash memory, return @code{-1}.
@smallexample
unsigned char __builtin_avr_insert_bits (unsigned long map,
unsigned char bits,
unsigned char val)
@end smallexample
@noindent
@item uint8_t __builtin_avr_insert_bits (uint32_t map, uint8_t bits, uint8_t val)
Insert bits from @var{bits} into @var{val} and return the resulting
value. The nibbles of @var{map} determine how the insertion is
performed: Let @var{X} be the @var{n}-th nibble of @var{map}
......@@ -12840,13 +12823,29 @@ __builtin_avr_insert_bits (0xffff3210, bits, val)
__builtin_avr_insert_bits (0x01234567, bits, 0)
@end smallexample
@smallexample
void __builtin_avr_nops (unsigned count)
@end smallexample
@item void __builtin_avr_nops (unsigned count)
Insert @var{count} @code{NOP} instructions.
The number of instructions must be a compile-time integer constant.
@end table
@noindent
Insert @code{count} @code{NOP} instructions.
The number of instructions must be a compile-time integer constant.
There are many more AVR-specific built-in functions that are used to
implement the ISO/IEC TR 18037 ``Embedded C'' fixed-point functions of
section 7.18a.6. You don't need to use these built-ins directly.
Instead, use the declarations as supplied by the @code{stdfix.h} header
with GNU-C99:
@smallexample
#include <stdfix.h>
// Re-interpret the bit representation of unsigned 16-bit
// integer @var{uval} as Q-format 0.16 value.
unsigned fract get_bits (uint_ur_t uval)
@{
return urbits (uval);
@}
@end smallexample
@node Blackfin Built-in Functions
@subsection Blackfin Built-in Functions
......
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