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-rw-r--r--libc/string/bfin/memcmp.S101
1 files changed, 101 insertions, 0 deletions
diff --git a/libc/string/bfin/memcmp.S b/libc/string/bfin/memcmp.S
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+/* memcmp.S
+ * Copyright (C) 2003, 2005, 2006 Analog Devices Inc., All Rights Reserved.
+ *
+ * This file is subject to the terms and conditions of the GNU Library General
+ * Public License. See the file "COPYING.LIB" in the main directory of this
+ * archive for more details.
+ *
+ * Non-LGPL License also available as part of VisualDSP++
+ * http://www.analog.com/processors/resources/crosscore/visualDspDevSoftware.html
+ */
+
+/* int memcmp(const void *s1, const void *s2, size_t n);
+ * R0 = First Address (s1)
+ * R1 = Second Address (s2)
+ * R2 = count (n)
+ *
+ * Favours word aligned data.
+ */
+
+.text
+
+.align 2
+
+.global _memcmp
+.type _memcmp, STT_FUNC
+_memcmp:
+ I1 = P3;
+ P0 = R0; // P0 = s1 address
+ P3 = R1; // P3 = s2 Address
+ P2 = R2 ; // P2 = count
+ CC = R2 <= 7(IU);
+ IF CC JUMP too_small;
+ I0 = R1; // s2
+ R1 = R1 | R0; // OR addresses together
+ R1 <<= 30; // check bottom two bits
+ CC = AZ; // AZ set if zero.
+ IF !CC JUMP bytes ; // Jump if addrs not aligned.
+
+ P1 = P2 >> 2; // count = n/4
+ R3 = 3;
+ R2 = R2 & R3; // remainder
+ P2 = R2; // set remainder
+
+ LSETUP (quad_loop_s , quad_loop_e) LC0=P1;
+quad_loop_s:
+#if !defined(__WORKAROUND_AVOID_DAG1)
+ MNOP || R0 = [P0++] || R1 = [I0++];
+#else
+ R0 = [P0++];
+ R1 = [I0++];
+#endif
+ CC = R0 == R1;
+ IF !CC JUMP quad_different;
+quad_loop_e:
+ NOP;
+
+ P3 = I0; // s2
+too_small:
+ CC = P2 == 0; //Check zero count
+ IF CC JUMP finished; // very unlikely
+
+bytes:
+ LSETUP (byte_loop_s , byte_loop_e) LC0=P2;
+byte_loop_s:
+ R1 = B[P3++](Z); // *s2
+ R0 = B[P0++](Z); // *s1
+ CC = R0 == R1;
+ IF !CC JUMP different;
+byte_loop_e:
+ NOP;
+
+different:
+ R0 = R0 - R1;
+ P3 = I1;
+ RTS;
+
+quad_different:
+ // We've read two quads which don't match.
+ // Can't just compare them, because we're
+ // a little-endian machine, so the MSBs of
+ // the regs occur at later addresses in the
+ // string.
+ // Arrange to re-read those two quads again,
+ // byte-by-byte.
+ P0 += -4; // back up to the start of the
+ P3 = I0; // quads, and increase the
+ P2 += 4; // remainder count
+ P3 += -4;
+ JUMP bytes;
+
+finished:
+ R0 = 0;
+ P3 = I1;
+ RTS;
+.size _memcmp,.-_memcmp
+
+libc_hidden_def (memcmp)
+
+#ifdef __UCLIBC_SUSV3_LEGACY__
+strong_alias (memcmp,bcmp)
+#endif