[atomic] add stdc atomic detection. (#7536)

3 files changed, 17 insertions, 18 deletions

diff --git a/libcpu/Kconfig b/libcpu/Kconfig
index 1de73b0a49..164520c4d4 100644
--- a/libcpu/Kconfig
+++ b/libcpu/Kconfig
@@ -166,7 +166,6 @@ config ARCH_ARMV8
     bool
     select ARCH_ARM
     select ARCH_ARM_MMU
-    select RT_USING_HW_ATOMIC
 
 config ARCH_MIPS
     bool
diff --git a/libcpu/arm/common/atomic_arm.c b/libcpu/arm/common/atomic_arm.c
index 023b2012df..18d186233f 100644
--- a/libcpu/arm/common/atomic_arm.c
+++ b/libcpu/arm/common/atomic_arm.c
@@ -166,7 +166,7 @@ rt_atomic_t rt_hw_atomic_flag_test_and_set(volatile rt_atomic_t *ptr)
     return oldval;
 }
 
-rt_atomic_t rt_hw_atomic_compare_exchange_strong(volatile rt_atomic_t *ptr, volatile rt_atomic_t *old, rt_atomic_t new)
+rt_atomic_t rt_hw_atomic_compare_exchange_strong(volatile rt_atomic_t *ptr, rt_atomic_t *old, rt_atomic_t new)
 {
     rt_atomic_t result;
     rt_atomic_t temp = *old;
diff --git a/libcpu/risc-v/common/atomic_riscv.c b/libcpu/risc-v/common/atomic_riscv.c
index 6a8cb99787..bc1561f2ee 100644
--- a/libcpu/risc-v/common/atomic_riscv.c
+++ b/libcpu/risc-v/common/atomic_riscv.c
@@ -12,7 +12,7 @@
 
 rt_atomic_t rt_hw_atomic_exchange(volatile rt_atomic_t *ptr, rt_atomic_t val)
 {
-    rt_atomic_t result;
+    rt_atomic_t result = 0;
 #if __riscv_xlen == 32
     asm volatile ("amoswap.w %0, %1, (%2)" : "=r"(result) : "r"(val), "r"(ptr) : "memory");
 #elif __riscv_xlen == 64
@@ -23,7 +23,7 @@ rt_atomic_t rt_hw_atomic_exchange(volatile rt_atomic_t *ptr, rt_atomic_t val)
 
 rt_atomic_t rt_hw_atomic_add(volatile rt_atomic_t *ptr, rt_atomic_t val)
 {
-    rt_atomic_t result;
+    rt_atomic_t result = 0;
 #if __riscv_xlen == 32
     asm volatile ("amoadd.w %0, %1, (%2)" : "=r"(result) : "r"(val), "r"(ptr) : "memory");
 #elif __riscv_xlen == 64
@@ -34,7 +34,7 @@ rt_atomic_t rt_hw_atomic_add(volatile rt_atomic_t *ptr, rt_atomic_t val)
 
 rt_atomic_t rt_hw_atomic_sub(volatile rt_atomic_t *ptr, rt_atomic_t val)
 {
-    rt_atomic_t result;
+    rt_atomic_t result = 0;
     val = -val;
 #if __riscv_xlen == 32
     asm volatile ("amoadd.w %0, %1, (%2)" : "=r"(result) : "r"(val), "r"(ptr) : "memory");
@@ -46,7 +46,7 @@ rt_atomic_t rt_hw_atomic_sub(volatile rt_atomic_t *ptr, rt_atomic_t val)
 
 rt_atomic_t rt_hw_atomic_xor(volatile rt_atomic_t *ptr, rt_atomic_t val)
 {
-    rt_atomic_t result;
+    rt_atomic_t result = 0;
 #if __riscv_xlen == 32
     asm volatile ("amoxor.w %0, %1, (%2)" : "=r"(result) : "r"(val), "r"(ptr) : "memory");
 #elif __riscv_xlen == 64
@@ -57,7 +57,7 @@ rt_atomic_t rt_hw_atomic_xor(volatile rt_atomic_t *ptr, rt_atomic_t val)
 
 rt_atomic_t rt_hw_atomic_and(volatile rt_atomic_t *ptr, rt_atomic_t val)
 {
-    rt_atomic_t result;
+    rt_atomic_t result = 0;
 #if __riscv_xlen == 32
     asm volatile ("amoand.w %0, %1, (%2)" : "=r"(result) : "r"(val), "r"(ptr) : "memory");
 #elif __riscv_xlen == 64
@@ -68,7 +68,7 @@ rt_atomic_t rt_hw_atomic_and(volatile rt_atomic_t *ptr, rt_atomic_t val)
 
 rt_atomic_t rt_hw_atomic_or(volatile rt_atomic_t *ptr, rt_atomic_t val)
 {
-    rt_atomic_t result;
+    rt_atomic_t result = 0;
 #if __riscv_xlen == 32
     asm volatile ("amoor.w %0, %1, (%2)" : "=r"(result) : "r"(val), "r"(ptr) : "memory");
 #elif __riscv_xlen == 64
@@ -79,7 +79,7 @@ rt_atomic_t rt_hw_atomic_or(volatile rt_atomic_t *ptr, rt_atomic_t val)
 
 rt_atomic_t rt_hw_atomic_load(volatile rt_atomic_t *ptr)
 {
-    rt_atomic_t result;
+    rt_atomic_t result = 0;
 #if __riscv_xlen == 32
     asm volatile ("amoxor.w %0, x0, (%1)" : "=r"(result) : "r"(ptr) : "memory");
 #elif __riscv_xlen == 64
@@ -90,7 +90,7 @@ rt_atomic_t rt_hw_atomic_load(volatile rt_atomic_t *ptr)
 
 void rt_hw_atomic_store(volatile rt_atomic_t *ptr, rt_atomic_t val)
 {
-    rt_atomic_t result;
+    rt_atomic_t result = 0;
 #if __riscv_xlen == 32
     asm volatile ("amoswap.w %0, %1, (%2)" : "=r"(result) : "r"(val), "r"(ptr) : "memory");
 #elif __riscv_xlen == 64
@@ -100,7 +100,7 @@ void rt_hw_atomic_store(volatile rt_atomic_t *ptr, rt_atomic_t val)
 
 rt_atomic_t rt_hw_atomic_flag_test_and_set(volatile rt_atomic_t *ptr)
 {
-    rt_atomic_t result;
+    rt_atomic_t result = 0;
     rt_atomic_t temp = 1;
 #if __riscv_xlen == 32
     asm volatile ("amoor.w %0, %1, (%2)" : "=r"(result) : "r"(temp), "r"(ptr) : "memory");
@@ -112,7 +112,7 @@ rt_atomic_t rt_hw_atomic_flag_test_and_set(volatile rt_atomic_t *ptr)
 
 void rt_hw_atomic_flag_clear(volatile rt_atomic_t *ptr)
 {
-    rt_atomic_t result;
+    rt_atomic_t result = 0;
 #if __riscv_xlen == 32
     asm volatile ("amoand.w %0, x0, (%1)" : "=r"(result) :"r"(ptr) : "memory");
 #elif __riscv_xlen == 64
@@ -120,16 +120,16 @@ void rt_hw_atomic_flag_clear(volatile rt_atomic_t *ptr)
 #endif
 }
 
-rt_atomic_t rt_hw_atomic_compare_exchange_strong(volatile rt_atomic_t *ptr, volatile rt_atomic_t *old, rt_atomic_t new)
+rt_atomic_t rt_hw_atomic_compare_exchange_strong(volatile rt_atomic_t *ptr, rt_atomic_t *old, rt_atomic_t desired)
 {
     rt_atomic_t tmp = *old;
-    rt_atomic_t result;
+    rt_atomic_t result = 0;
 #if __riscv_xlen == 32
     asm volatile(
             " fence iorw, ow\n"
             "1: lr.w.aq  %[result], (%[ptr])\n"
             "   bne      %[result], %[tmp], 2f\n"
-            "   sc.w.rl  %[tmp], %[new], (%[ptr])\n"
+            "   sc.w.rl  %[tmp], %[desired], (%[ptr])\n"
             "   bnez     %[tmp], 1b\n"
             "   li  %[result], 1\n"
             "   j 3f\n"
@@ -137,14 +137,14 @@ rt_atomic_t rt_hw_atomic_compare_exchange_strong(volatile rt_atomic_t *ptr, vola
             "   li  %[result], 0\n"
             " 3:\n"
             : [result]"+r" (result), [tmp]"+r" (tmp), [ptr]"+r" (ptr)
-            : [new]"r" (new), [old]"r"(old)
+            : [desired]"r" (desired), [old]"r"(old)
             : "memory");
 #elif __riscv_xlen == 64
     asm volatile(
             " fence iorw, ow\n"
             "1: lr.d.aq  %[result], (%[ptr])\n"
             "   bne      %[result], %[tmp], 2f\n"
-            "   sc.d.rl  %[tmp], %[new], (%[ptr])\n"
+            "   sc.d.rl  %[tmp], %[desired], (%[ptr])\n"
             "   bnez     %[tmp], 1b\n"
             "   li  %[result], 1\n"
             "   j 3f\n"
@@ -152,7 +152,7 @@ rt_atomic_t rt_hw_atomic_compare_exchange_strong(volatile rt_atomic_t *ptr, vola
             "   li  %[result], 0\n"
             " 3:\n"
             : [result]"+r" (result), [tmp]"+r" (tmp), [ptr]"+r" (ptr)
-            : [new]"r" (new), [old]"r"(old)
+            : [desired]"r" (desired), [old]"r"(old)
             : "memory");
 #endif
     return result;