Properly initialise the C runtime environment
This patch makes sure the C runtime environment is properly
initialised before executing any C code.
- Zero-initialise NOBITS sections (e.g. the bss section).
- Relocate BL1 data from ROM to RAM.
Change-Id: I0da81b417b2f0d1f7ef667cc5131b1e47e22571f
diff --git a/lib/arch/aarch64/misc_helpers.S b/lib/arch/aarch64/misc_helpers.S
index 05e90f9..e36fdfa 100644
--- a/lib/arch/aarch64/misc_helpers.S
+++ b/lib/arch/aarch64/misc_helpers.S
@@ -75,6 +75,8 @@
.globl eret
.globl smc
+ .globl zeromem16
+ .globl memcpy16
.section .text, "ax"
@@ -285,3 +287,54 @@
smc:; .type smc, %function
smc #0
+
+/* -----------------------------------------------------------------------
+ * void zeromem16(void *mem, unsigned int length);
+ *
+ * Initialise a memory region to 0.
+ * The memory address must be 16-byte aligned.
+ * -----------------------------------------------------------------------
+ */
+zeromem16:
+ add x2, x0, x1
+/* zero 16 bytes at a time */
+z_loop16:
+ sub x3, x2, x0
+ cmp x3, #16
+ b.lt z_loop1
+ stp xzr, xzr, [x0], #16
+ b z_loop16
+/* zero byte per byte */
+z_loop1:
+ cmp x0, x2
+ b.eq z_end
+ strb wzr, [x0], #1
+ b z_loop1
+z_end: ret
+
+
+/* --------------------------------------------------------------------------
+ * void memcpy16(void *dest, const void *src, unsigned int length)
+ *
+ * Copy length bytes from memory area src to memory area dest.
+ * The memory areas should not overlap.
+ * Destination and source addresses must be 16-byte aligned.
+ * --------------------------------------------------------------------------
+ */
+memcpy16:
+/* copy 16 bytes at a time */
+m_loop16:
+ cmp x2, #16
+ b.lt m_loop1
+ ldp x3, x4, [x1], #16
+ stp x3, x4, [x0], #16
+ sub x2, x2, #16
+ b m_loop16
+/* copy byte per byte */
+m_loop1:
+ cbz x2, m_end
+ ldrb w3, [x1], #1
+ strb w3, [x0], #1
+ subs x2, x2, #1
+ b.ne m_loop1
+m_end: ret