Hello,
for the RISC-V target, I would like to use the -march=rv64imc ISA variant.
However, there is an issue with the libatomic for this target in the RTEMS
configuration. For this test code:
#include <stdatomic.h>
bool tas(atomic_flag *f)
{
return atomic_flag_test_and_set(f);
}
GCC 15 generates:
riscv-rtems6-gcc -O2 -S -o - -march=rv64imc -mabi=lp64 test.c
.file "test.c"
.option nopic
.attribute arch, "rv64i2p1_m2p0_c2p0_zmmul1p0_zca1p0"
.attribute unaligned_access, 0
.attribute stack_align, 16
.text
.align 1
.globl tas
.type tas, @function
tas:
li a1,5
tail __atomic_test_and_set
.size tas, .-tas
.ident "GCC: 15.1.1 20250517"
.section .note.GNU-stack,"",@progbits
In the corresponding libatomic.a multilib, there are the following functions
(omitting *_4, *_8, *_16 variants which exist for all *_1 variants):
__atomic_add_fetch_1
__atomic_and_fetch_1
__atomic_compare_exchange
__atomic_compare_exchange_1
__atomic_exchange
__atomic_exchange_1
__atomic_feraiseexcept
__atomic_fetch_add_1
__atomic_fetch_and_1
__atomic_fetch_nand_1
__atomic_fetch_or_1
__atomic_fetch_sub_1
__atomic_fetch_xor_1
__atomic_is_lock_free
__atomic_load
__atomic_load_1
__atomic_nand_fetch_1
__atomic_or_fetch_1
__atomic_store
__atomic_store_1
__atomic_sub_fetch_1
__atomic_test_and_set_1
__atomic_xor_fetch_1
Some operations have a variant without a _1, _2, _4, _8, and _16 postfix
(example: __atomic_store). Others do not have such a variant, examples:
__atomic_test_and_set_1, __atomic_add_fetch_1.
I am a bit clueless what is going on here. Are the missing variants a libatomic
configuration error? Is it a general configuration error or specific to RTEMS?
--
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