From fa602a671352299822ddd3ccbb5ce69163f9da87 Mon Sep 17 00:00:00 2001
From: xunyingya <619765394@qq.com>
Date: Fri, 7 Nov 2025 11:24:47 +0800
Subject: [PATCH 1/3] [libcpu][arm] fix: correct FPU stack initialization order
 and alignment on Cortex-A

---
 libcpu/arm/cortex-a/stack.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/libcpu/arm/cortex-a/stack.c b/libcpu/arm/cortex-a/stack.c
index 4c955677f87..73f73e67efe 100644
--- a/libcpu/arm/cortex-a/stack.c
+++ b/libcpu/arm/cortex-a/stack.c
@@ -31,6 +31,7 @@ rt_uint8_t *rt_hw_stack_init(void *tentry, void *parameter,
                              rt_uint8_t *stack_addr, void *texit)
 {
     rt_uint32_t *stk;
+    rt_uint32_t i = 0;
 
     stack_addr += sizeof(rt_uint32_t);
     stack_addr  = (rt_uint8_t *)RT_ALIGN_DOWN((rt_uint32_t)stack_addr, 8);
@@ -61,7 +62,25 @@ rt_uint8_t *rt_hw_stack_init(void *tentry, void *parameter,
     *(--stk) = 0;       /* user sp*/
 #endif
 #ifdef RT_USING_FPU
-    *(--stk) = 0;       /* not use fpu*/
+    /* 1. D0-D15 */
+    for (i = 0; i <= 15; i++)
+    {
+        *(--stk) = 0x00000000;
+        *(--stk) = 0x00000000;
+    }
+
+    /* 2. D16-D31 */
+    for (i = 16; i <= 31; i++)
+    {
+        *(--stk) = 0x00000000;
+        *(--stk) = 0x00000000;
+    }
+
+    /* 3. FPSCR */
+    *(--stk) = 0x00000000;
+
+    /* 4. FPEXC: EN=1 */
+    *(--stk) = 0x40000000; 
 #endif
 
     /* return task's current stack address */

From aecd471a38a56b869741053d2ca37cba6879b31a Mon Sep 17 00:00:00 2001
From: xunyingya <619765394@qq.com>
Date: Fri, 7 Nov 2025 16:35:23 +0800
Subject: [PATCH 2/3] [libcpu][arm] fix: remove initialization in declaration
 to pass CI check

---
 libcpu/arm/cortex-a/stack.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libcpu/arm/cortex-a/stack.c b/libcpu/arm/cortex-a/stack.c
index 73f73e67efe..56fe5778167 100644
--- a/libcpu/arm/cortex-a/stack.c
+++ b/libcpu/arm/cortex-a/stack.c
@@ -31,7 +31,7 @@ rt_uint8_t *rt_hw_stack_init(void *tentry, void *parameter,
                              rt_uint8_t *stack_addr, void *texit)
 {
     rt_uint32_t *stk;
-    rt_uint32_t i = 0;
+    rt_uint32_t i;
 
     stack_addr += sizeof(rt_uint32_t);
     stack_addr  = (rt_uint8_t *)RT_ALIGN_DOWN((rt_uint32_t)stack_addr, 8);

From d074a7e4899420939f527a05d31ee3e96488630a Mon Sep 17 00:00:00 2001
From: xunyingya <619765394@qq.com>
Date: Mon, 10 Nov 2025 09:35:09 +0800
Subject: [PATCH 3/3] [libcpu][arm] fix: correct FPU stack initialization
 sequence and alignment for Cortex-A

---
 libcpu/arm/cortex-a/stack.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libcpu/arm/cortex-a/stack.c b/libcpu/arm/cortex-a/stack.c
index 56fe5778167..72e531612d0 100644
--- a/libcpu/arm/cortex-a/stack.c
+++ b/libcpu/arm/cortex-a/stack.c
@@ -31,7 +31,9 @@ rt_uint8_t *rt_hw_stack_init(void *tentry, void *parameter,
                              rt_uint8_t *stack_addr, void *texit)
 {
     rt_uint32_t *stk;
+#ifdef RT_USING_FPU
     rt_uint32_t i;
+#endif
 
     stack_addr += sizeof(rt_uint32_t);
     stack_addr  = (rt_uint8_t *)RT_ALIGN_DOWN((rt_uint32_t)stack_addr, 8);