This commit removes the `z_` prefix from the stdio syscall functions
(`z_zephyr_write_stdout` and `z_zephyr_read_stdin`) since it is
redundant and does not align with the convention used by the equivalent
minimal libc syscall functions (e.g. `zephyr_fputc` and
`zephyr_fwrite`).
Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
ARC MWDT toolchain misses stdout hooks implementation and
itimerspec structure in timespec header. Let's add them in
arcmwdt compatibility layer.
The implementation was inspired by libc-hooks.c for NEWLIB.
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Evgeniy Paltsev <PaltsevEvgeniy@gmail.com>
rand() and srand() are pseudo-random number generator functions
defined in ISO C. This implementation uses the Linear Congruential
Generator (LCG) algorithm with the following parameters, which are the
same as used in GNU Libc "TYPE_0" algorithm.
Modulus 2^31
Multiplier 1103515245
Increment 12345
Output Bits 30..0
Note that the default algorithm used by GNU Libc is not TYPE_0, and
TYPE_0 should be selected first by an initstate() call as shown below.
All global variables in a C library must be routed to a memory
partition in order to be used by user-mode applications when
CONFIG_USERSPACE is enabled. Thus, srand_seed is marked as
such. z_libc_partition is originally used by the Newlib C library but
it's generic enough to be used by either the minimal libc or the
newlib.
All other functions in the Minimal C library, however, don't require
global variables/states. Unconditionally using z_libc_partition with
the minimal libc might be a problem for applications utilizing many
custom memory partitions on platforms with a limited number of MPU
regions (eg. Cortex M0/M3). This commit introduces a kconfig option
CONFIG_MINIMAL_LIBC_RAND so that applications can enable the
functions if needed. The option is disabled by default.
Because this commit _does_ implement rand() and srand(), our coding
guideline check on GitHub Action finds it as a violation.
Error: lib/libc/minimal/include/stdlib.h:45:WARNING: Violation to
rule 21.2 (Should not used a reserved identifier) - srand
But this is false positive.
The following is a simple test program for LCG with GNU Libc.
#include <stdio.h>
#include <stdlib.h>
int main()
{
static char state[8];
/* Switch GLIBC to use LCG/TYPE_0 generator type. */
initstate(0, state, sizeof(state));
srand(1); /* Or any other value. */
printf("%d\n", rand());
printf("%d\n", rand());
return 0;
}
See initstate(3p) for more detail about how to use LCG in GLIBC.
Signed-off-by: Yasushi SHOJI <yashi@spacecubics.com>
Adds the necessary bits to initialize TLS in the stack
area and sets up CPU registers during context switch.
Note that since Cortex-M does not have the thread ID or
process ID register needed to store TLS pointer at runtime
for toolchain to access thread data, a global variable is
used instead.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
The z_libc_partition was only enabled when newlib is being used,
and/or stack canaries are needed. This adds a hidden option
where this partition can be enabled if needed, regardless of
whether newlib is used or stack canaries are needed.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
move misc/libc-hooks.h to sys/libc-hooks.h and
create a shim for backward-compatibility.
No functional changes to the headers.
A warning in the shim can be controlled with CONFIG_COMPAT_INCLUDES.
Related to #16539
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
