MIPS: microMIPS: Optimise 'memset' core library function.

Optimise 'memset' to use microMIPS instructions and/or optimisations
for binary size reduction. When the microMIPS ISA is not being used,
the library function compiles to the original binary code.

Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>

2 files changed, 56 insertions, 30 deletions

diff --git a/arch/mips/include/asm/asm.h b/arch/mips/include/asm/asm.h
index 164a21e65b42..879691d194af 100644
--- a/arch/mips/include/asm/asm.h
+++ b/arch/mips/include/asm/asm.h
@@ -296,6 +296,7 @@ symbol		=	value
 #define LONG_SUBU       subu
 #define LONG_L          lw
 #define LONG_S          sw
+#define LONG_SP         swp
 #define LONG_SLL        sll
 #define LONG_SLLV       sllv
 #define LONG_SRL        srl
@@ -318,6 +319,7 @@ symbol		=	value
 #define LONG_SUBU       dsubu
 #define LONG_L          ld
 #define LONG_S          sd
+#define LONG_SP         sdp
 #define LONG_SLL        dsll
 #define LONG_SLLV       dsllv
 #define LONG_SRL        dsrl
diff --git a/arch/mips/lib/memset.S b/arch/mips/lib/memset.S
index 053d3b0b0317..0580194e7402 100644
--- a/arch/mips/lib/memset.S
+++ b/arch/mips/lib/memset.S
@@ -5,7 +5,8 @@
  *
  * Copyright (C) 1998, 1999, 2000 by Ralf Baechle
  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
- * Copyright (C) 2007  Maciej W. Rozycki
+ * Copyright (C) 2007 by Maciej W. Rozycki
+ * Copyright (C) 2011, 2012 MIPS Technologies, Inc.
  */
 #include <asm/asm.h>
 #include <asm/asm-offsets.h>
@@ -19,6 +20,20 @@
 #define LONG_S_R sdr
 #endif
 
+#ifdef CONFIG_CPU_MICROMIPS
+#define STORSIZE (LONGSIZE * 2)
+#define STORMASK (STORSIZE - 1)
+#define FILL64RG t8
+#define FILLPTRG t7
+#undef  LONG_S
+#define LONG_S LONG_SP
+#else
+#define STORSIZE LONGSIZE
+#define STORMASK LONGMASK
+#define FILL64RG a1
+#define FILLPTRG t0
+#endif
+
 #define EX(insn,reg,addr,handler)                       \
 9:      insn    reg, addr;                              \
         .section __ex_table,"a";                        \
@@ -26,23 +41,25 @@
         .previous
 
         .macro  f_fill64 dst, offset, val, fixup
-        EX(LONG_S, \val, (\offset +  0 * LONGSIZE)(\dst), \fixup)
-        EX(LONG_S, \val, (\offset +  1 * LONGSIZE)(\dst), \fixup)
-        EX(LONG_S, \val, (\offset +  2 * LONGSIZE)(\dst), \fixup)
-        EX(LONG_S, \val, (\offset +  3 * LONGSIZE)(\dst), \fixup)
-        EX(LONG_S, \val, (\offset +  4 * LONGSIZE)(\dst), \fixup)
-        EX(LONG_S, \val, (\offset +  5 * LONGSIZE)(\dst), \fixup)
-        EX(LONG_S, \val, (\offset +  6 * LONGSIZE)(\dst), \fixup)
-        EX(LONG_S, \val, (\offset +  7 * LONGSIZE)(\dst), \fixup)
-#if LONGSIZE == 4
-        EX(LONG_S, \val, (\offset +  8 * LONGSIZE)(\dst), \fixup)
-        EX(LONG_S, \val, (\offset +  9 * LONGSIZE)(\dst), \fixup)
-        EX(LONG_S, \val, (\offset + 10 * LONGSIZE)(\dst), \fixup)
-        EX(LONG_S, \val, (\offset + 11 * LONGSIZE)(\dst), \fixup)
-        EX(LONG_S, \val, (\offset + 12 * LONGSIZE)(\dst), \fixup)
-        EX(LONG_S, \val, (\offset + 13 * LONGSIZE)(\dst), \fixup)
-        EX(LONG_S, \val, (\offset + 14 * LONGSIZE)(\dst), \fixup)
-        EX(LONG_S, \val, (\offset + 15 * LONGSIZE)(\dst), \fixup)
+        EX(LONG_S, \val, (\offset +  0 * STORSIZE)(\dst), \fixup)
+        EX(LONG_S, \val, (\offset +  1 * STORSIZE)(\dst), \fixup)
+        EX(LONG_S, \val, (\offset +  2 * STORSIZE)(\dst), \fixup)
+        EX(LONG_S, \val, (\offset +  3 * STORSIZE)(\dst), \fixup)
+#if ((defined(CONFIG_CPU_MICROMIPS) && (LONGSIZE == 4)) || !defined(CONFIG_CPU_MICROMIPS))
+        EX(LONG_S, \val, (\offset +  4 * STORSIZE)(\dst), \fixup)
+        EX(LONG_S, \val, (\offset +  5 * STORSIZE)(\dst), \fixup)
+        EX(LONG_S, \val, (\offset +  6 * STORSIZE)(\dst), \fixup)
+        EX(LONG_S, \val, (\offset +  7 * STORSIZE)(\dst), \fixup)
+#endif
+#if (!defined(CONFIG_CPU_MICROMIPS) && (LONGSIZE == 4))
+        EX(LONG_S, \val, (\offset +  8 * STORSIZE)(\dst), \fixup)
+        EX(LONG_S, \val, (\offset +  9 * STORSIZE)(\dst), \fixup)
+        EX(LONG_S, \val, (\offset + 10 * STORSIZE)(\dst), \fixup)
+        EX(LONG_S, \val, (\offset + 11 * STORSIZE)(\dst), \fixup)
+        EX(LONG_S, \val, (\offset + 12 * STORSIZE)(\dst), \fixup)
+        EX(LONG_S, \val, (\offset + 13 * STORSIZE)(\dst), \fixup)
+        EX(LONG_S, \val, (\offset + 14 * STORSIZE)(\dst), \fixup)
+        EX(LONG_S, \val, (\offset + 15 * STORSIZE)(\dst), \fixup)
 #endif
         .endm
 
@@ -71,16 +88,20 @@ LEAF(memset)
 1:
 
 FEXPORT(__bzero)
-        sltiu           t0, a2, LONGSIZE        /* very small region? */
+        sltiu           t0, a2, STORSIZE        /* very small region? */
         bnez            t0, .Lsmall_memset
-         andi           t0, a0, LONGMASK        /* aligned? */
+         andi           t0, a0, STORMASK        /* aligned? */
 
+#ifdef CONFIG_CPU_MICROMIPS
+        move            t8, a1                  /* used by 'swp' instruction */
+        move            t9, a1
+#endif
 #ifndef CONFIG_CPU_DADDI_WORKAROUNDS
         beqz            t0, 1f
-         PTR_SUBU       t0, LONGSIZE            /* alignment in bytes */
+         PTR_SUBU       t0, STORSIZE            /* alignment in bytes */
 #else
         .set            noat
-        li              AT, LONGSIZE
+        li              AT, STORSIZE
         beqz            t0, 1f
          PTR_SUBU       t0, AT                  /* alignment in bytes */
         .set            at
@@ -99,24 +120,27 @@ FEXPORT(__bzero)
 1:      ori             t1, a2, 0x3f            /* # of full blocks */
         xori            t1, 0x3f
         beqz            t1, .Lmemset_partial    /* no block to fill */
-         andi           t0, a2, 0x40-LONGSIZE
+         andi           t0, a2, 0x40-STORSIZE
 
         PTR_ADDU        t1, a0                  /* end address */
         .set            reorder
 1:      PTR_ADDIU       a0, 64
         R10KCBARRIER(0(ra))
-        f_fill64 a0, -64, a1, .Lfwd_fixup
+        f_fill64 a0, -64, FILL64RG, .Lfwd_fixup
         bne             t1, a0, 1b
         .set            noreorder
 
 .Lmemset_partial:
         R10KCBARRIER(0(ra))
         PTR_LA          t1, 2f                  /* where to start */
+#ifdef CONFIG_CPU_MICROMIPS
+        LONG_SRL        t7, t0, 1
+#endif
 #if LONGSIZE == 4
-        PTR_SUBU        t1, t0
+        PTR_SUBU        t1, FILLPTRG
 #else
         .set            noat
-        LONG_SRL                AT, t0, 1
+        LONG_SRL        AT, FILLPTRG, 1
         PTR_SUBU        t1, AT
         .set            at
 #endif
@@ -126,9 +150,9 @@ FEXPORT(__bzero)
         .set            push
         .set            noreorder
         .set            nomacro
-        f_fill64 a0, -64, a1, .Lpartial_fixup   /* ... but first do longs ... */
+        f_fill64 a0, -64, FILL64RG, .Lpartial_fixup     /* ... but first do longs ... */
 2:      .set            pop
-        andi            a2, LONGMASK            /* At most one long to go */
+        andi            a2, STORMASK            /* At most one long to go */
 
         beqz            a2, 1f
          PTR_ADDU       a0, a2                  /* What's left */
@@ -169,7 +193,7 @@ FEXPORT(__bzero)
 
 .Lpartial_fixup:
         PTR_L           t0, TI_TASK($28)
-        andi            a2, LONGMASK
+        andi            a2, STORMASK
         LONG_L          t0, THREAD_BUADDR(t0)
         LONG_ADDU       a2, t1
         jr              ra
@@ -177,4 +201,4 @@ FEXPORT(__bzero)
 
 .Llast_fixup:
         jr              ra
-         andi           v1, a2, LONGMASK
+         andi           v1, a2, STORMASK