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-rw-r--r--arch/arm/lib/memzero.S44
1 files changed, 44 insertions, 0 deletions
diff --git a/arch/arm/lib/memzero.S b/arch/arm/lib/memzero.S
index abf2508e822..b8f79d80ee9 100644
--- a/arch/arm/lib/memzero.S
+++ b/arch/arm/lib/memzero.S
@@ -39,6 +39,9 @@ ENTRY(__memzero)
*/
cmp r1, #16 @ 1 we can skip this chunk if we
blt 4f @ 1 have < 16 bytes
+
+#if ! CALGN(1)+0
+
/*
* We need an extra register for this loop - save the return address and
* use the LR
@@ -64,6 +67,47 @@ ENTRY(__memzero)
stmneia r0!, {r2, r3, ip, lr} @ 4
ldr lr, [sp], #4 @ 1
+#else
+
+/*
+ * This version aligns the destination pointer in order to write
+ * whole cache lines at once.
+ */
+
+ stmfd sp!, {r4-r7, lr}
+ mov r4, r2
+ mov r5, r2
+ mov r6, r2
+ mov r7, r2
+ mov ip, r2
+ mov lr, r2
+
+ cmp r1, #96
+ andgts ip, r0, #31
+ ble 3f
+
+ rsb ip, ip, #32
+ sub r1, r1, ip
+ movs ip, ip, lsl #(32 - 4)
+ stmcsia r0!, {r4, r5, r6, r7}
+ stmmiia r0!, {r4, r5}
+ movs ip, ip, lsl #2
+ strcs r2, [r0], #4
+
+3: subs r1, r1, #64
+ stmgeia r0!, {r2-r7, ip, lr}
+ stmgeia r0!, {r2-r7, ip, lr}
+ bgt 3b
+ ldmeqfd sp!, {r4-r7, pc}
+
+ tst r1, #32
+ stmneia r0!, {r2-r7, ip, lr}
+ tst r1, #16
+ stmneia r0!, {r4-r7}
+ ldmfd sp!, {r4-r7, lr}
+
+#endif
+
4: tst r1, #8 @ 1 8 bytes or more?
stmneia r0!, {r2, r3} @ 2
tst r1, #4 @ 1 4 bytes or more?