riscv: assembler versions of memcpy, memmove, memset
Provide optimized versions of memcpy(), memmove(), memset() copied from
the Linux kernel.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
diff --git a/arch/riscv/lib/memcpy.S b/arch/riscv/lib/memcpy.S
new file mode 100644
index 0000000..51ab716
--- /dev/null
+++ b/arch/riscv/lib/memcpy.S
@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2013 Regents of the University of California
+ */
+
+#include <linux/linkage.h>
+#include <asm/asm.h>
+
+/* void *memcpy(void *, const void *, size_t) */
+ENTRY(__memcpy)
+WEAK(memcpy)
+ move t6, a0 /* Preserve return value */
+
+ /* Defer to byte-oriented copy for small sizes */
+ sltiu a3, a2, 128
+ bnez a3, 4f
+ /* Use word-oriented copy only if low-order bits match */
+ andi a3, t6, SZREG-1
+ andi a4, a1, SZREG-1
+ bne a3, a4, 4f
+
+ beqz a3, 2f /* Skip if already aligned */
+ /*
+ * Round to nearest double word-aligned address
+ * greater than or equal to start address
+ */
+ andi a3, a1, ~(SZREG-1)
+ addi a3, a3, SZREG
+ /* Handle initial misalignment */
+ sub a4, a3, a1
+1:
+ lb a5, 0(a1)
+ addi a1, a1, 1
+ sb a5, 0(t6)
+ addi t6, t6, 1
+ bltu a1, a3, 1b
+ sub a2, a2, a4 /* Update count */
+
+2:
+ andi a4, a2, ~((16*SZREG)-1)
+ beqz a4, 4f
+ add a3, a1, a4
+3:
+ REG_L a4, 0(a1)
+ REG_L a5, SZREG(a1)
+ REG_L a6, 2*SZREG(a1)
+ REG_L a7, 3*SZREG(a1)
+ REG_L t0, 4*SZREG(a1)
+ REG_L t1, 5*SZREG(a1)
+ REG_L t2, 6*SZREG(a1)
+ REG_L t3, 7*SZREG(a1)
+ REG_L t4, 8*SZREG(a1)
+ REG_L t5, 9*SZREG(a1)
+ REG_S a4, 0(t6)
+ REG_S a5, SZREG(t6)
+ REG_S a6, 2*SZREG(t6)
+ REG_S a7, 3*SZREG(t6)
+ REG_S t0, 4*SZREG(t6)
+ REG_S t1, 5*SZREG(t6)
+ REG_S t2, 6*SZREG(t6)
+ REG_S t3, 7*SZREG(t6)
+ REG_S t4, 8*SZREG(t6)
+ REG_S t5, 9*SZREG(t6)
+ REG_L a4, 10*SZREG(a1)
+ REG_L a5, 11*SZREG(a1)
+ REG_L a6, 12*SZREG(a1)
+ REG_L a7, 13*SZREG(a1)
+ REG_L t0, 14*SZREG(a1)
+ REG_L t1, 15*SZREG(a1)
+ addi a1, a1, 16*SZREG
+ REG_S a4, 10*SZREG(t6)
+ REG_S a5, 11*SZREG(t6)
+ REG_S a6, 12*SZREG(t6)
+ REG_S a7, 13*SZREG(t6)
+ REG_S t0, 14*SZREG(t6)
+ REG_S t1, 15*SZREG(t6)
+ addi t6, t6, 16*SZREG
+ bltu a1, a3, 3b
+ andi a2, a2, (16*SZREG)-1 /* Update count */
+
+4:
+ /* Handle trailing misalignment */
+ beqz a2, 6f
+ add a3, a1, a2
+
+ /* Use word-oriented copy if co-aligned to word boundary */
+ or a5, a1, t6
+ or a5, a5, a3
+ andi a5, a5, 3
+ bnez a5, 5f
+7:
+ lw a4, 0(a1)
+ addi a1, a1, 4
+ sw a4, 0(t6)
+ addi t6, t6, 4
+ bltu a1, a3, 7b
+
+ ret
+
+5:
+ lb a4, 0(a1)
+ addi a1, a1, 1
+ sb a4, 0(t6)
+ addi t6, t6, 1
+ bltu a1, a3, 5b
+6:
+ ret
+END(__memcpy)