1 files changed, 53 insertions, 0 deletions
diff --git a/arch/src/armv7-m/armv7-crt0.S b/arch/src/armv7-m/armv7-crt0.S
new file mode 100644
index 0000000..f01ef1a
--- /dev/null
+++ b/arch/src/armv7-m/armv7-crt0.S
@@ -0,0 +1,53 @@
+ /*
+ * Copyright (c) 2019, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Description:
+ *      startup file.
+ */
+
+
+    .syntax unified
+
+    .text
+
+    .global start
+    .thumb_func
+    .func start
+start:
+    /* Load .data, which is 4-byte aligned */
+    ldr     r1, =__DATA_SIZE__
+    cmp     r1, #0
+    beq     6f
+    ldr     r0, =__DATA_LMA_START__
+    ldr     r2, =__DATA_START__
+    cmp     r0, r2
+    beq     6f
+5:
+    ldr     r3, [r0], #4
+    str     r3, [r2], #4
+    subs    r1, #4
+    bne     5b
+
+6:
+    /* Clear .bss, which is also 4-byte aligned */
+    ldr     r1, =__BSS_SIZE__
+    cmp     r1, #0
+    beq     8f
+    ldr     r0, =__BSS_START__
+    mov     r2, #0
+7:
+    str     r2, [r0], #4
+    subs    r1, #4
+    bne     7b
+
+8:
+    dsb
+    bl      arm_main
+
+9:
+    wfi
+    b 9b
+    .pool
+    .endfunc