Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 259 insertions, 0 deletions

diff --git a/arch/alpha/lib/ev6-divide.S b/arch/alpha/lib/ev6-divide.S
new file mode 100644
index 000000000000..2a82b9be93fa
--- /dev/null
+++ b/arch/alpha/lib/ev6-divide.S
@@ -0,0 +1,259 @@
+/*
+ * arch/alpha/lib/ev6-divide.S
+ *
+ * 21264 version contributed by Rick Gorton <rick.gorton@alpha-processor.com>
+ *
+ * Alpha division..
+ */
+
+/*
+ * The alpha chip doesn't provide hardware division, so we have to do it
+ * by hand.  The compiler expects the functions
+ *
+ *      __divqu: 64-bit unsigned long divide
+ *      __remqu: 64-bit unsigned long remainder
+ *      __divqs/__remqs: signed 64-bit
+ *      __divlu/__remlu: unsigned 32-bit
+ *      __divls/__remls: signed 32-bit
+ *
+ * These are not normal C functions: instead of the normal
+ * calling sequence, these expect their arguments in registers
+ * $24 and $25, and return the result in $27. Register $28 may
+ * be clobbered (assembly temporary), anything else must be saved. 
+ *
+ * In short: painful.
+ *
+ * This is a rather simple bit-at-a-time algorithm: it's very good
+ * at dividing random 64-bit numbers, but the more usual case where
+ * the divisor is small is handled better by the DEC algorithm
+ * using lookup tables. This uses much less memory, though, and is
+ * nicer on the cache.. Besides, I don't know the copyright status
+ * of the DEC code.
+ */
+
+/*
+ * My temporaries:
+ *      $0 - current bit
+ *      $1 - shifted divisor
+ *      $2 - modulus/quotient
+ *
+ *      $23 - return address
+ *      $24 - dividend
+ *      $25 - divisor
+ *
+ *      $27 - quotient/modulus
+ *      $28 - compare status
+ *
+ * Much of the information about 21264 scheduling/coding comes from:
+ *      Compiler Writer's Guide for the Alpha 21264
+ *      abbreviated as 'CWG' in other comments here
+ *      ftp.digital.com/pub/Digital/info/semiconductor/literature/dsc-library.html
+ * Scheduling notation:
+ *      E       - either cluster
+ *      U       - upper subcluster; U0 - subcluster U0; U1 - subcluster U1
+ *      L       - lower subcluster; L0 - subcluster L0; L1 - subcluster L1
+ * Try not to change the actual algorithm if possible for consistency.
+ */
+
+#define halt .long 0
+
+/*
+ * Select function type and registers
+ */
+#define mask    $0
+#define divisor $1
+#define compare $28
+#define tmp1    $3
+#define tmp2    $4
+
+#ifdef DIV
+#define DIV_ONLY(x,y...) x,##y
+#define MOD_ONLY(x,y...)
+#define func(x) __div##x
+#define modulus $2
+#define quotient $27
+#define GETSIGN(x) xor $24,$25,x
+#define STACK 48
+#else
+#define DIV_ONLY(x,y...)
+#define MOD_ONLY(x,y...) x,##y
+#define func(x) __rem##x
+#define modulus $27
+#define quotient $2
+#define GETSIGN(x) bis $24,$24,x
+#define STACK 32
+#endif
+
+/*
+ * For 32-bit operations, we need to extend to 64-bit
+ */
+#ifdef INTSIZE
+#define ufunction func(lu)
+#define sfunction func(l)
+#define LONGIFY(x) zapnot x,15,x
+#define SLONGIFY(x) addl x,0,x
+#else
+#define ufunction func(qu)
+#define sfunction func(q)
+#define LONGIFY(x)
+#define SLONGIFY(x)
+#endif
+
+.set noat
+.align  4
+.globl  ufunction
+.ent    ufunction
+ufunction:
+        subq    $30,STACK,$30           # E :
+        .frame  $30,STACK,$23
+        .prologue 0
+
+7:      stq     $1, 0($30)              # L :
+        bis     $25,$25,divisor         # E :
+        stq     $2, 8($30)              # L : L U L U
+
+        bis     $24,$24,modulus         # E :
+        stq     $0,16($30)              # L :
+        bis     $31,$31,quotient        # E :
+        LONGIFY(divisor)                # E : U L L U
+
+        stq     tmp1,24($30)            # L :
+        LONGIFY(modulus)                # E :
+        bis     $31,1,mask              # E :
+        DIV_ONLY(stq tmp2,32($30))      # L : L U U L
+
+        beq     divisor, 9f                     /* div by zero */
+        /*
+         * In spite of the DIV_ONLY being either a non-instruction
+         * or an actual stq, the addition of the .align directive
+         * below ensures that label 1 is going to be nicely aligned
+         */
+
+        .align  4
+#ifdef INTSIZE
+        /*
+         * shift divisor left, using 3-bit shifts for
+         * 32-bit divides as we can't overflow. Three-bit
+         * shifts will result in looping three times less
+         * here, but can result in two loops more later.
+         * Thus using a large shift isn't worth it (and
+         * s8add pairs better than a sll..)
+         */
+1:      cmpult  divisor,modulus,compare # E :
+        s8addq  divisor,$31,divisor     # E :
+        s8addq  mask,$31,mask           # E :
+        bne     compare,1b              # U : U L U L
+#else
+1:      cmpult  divisor,modulus,compare # E :
+        nop                             # E :
+        nop                             # E :
+        blt     divisor, 2f             # U : U L U L
+
+        addq    divisor,divisor,divisor # E :
+        addq    mask,mask,mask          # E :
+        unop                            # E :
+        bne     compare,1b              # U : U L U L
+#endif
+
+        /* ok, start to go right again.. */
+2:
+        /*
+         * Keep things nicely bundled... use a nop instead of not
+         * having an instruction for DIV_ONLY
+         */
+#ifdef DIV
+        DIV_ONLY(addq quotient,mask,tmp2) # E :
+#else
+        nop                             # E :
+#endif
+        srl     mask,1,mask             # U :
+        cmpule  divisor,modulus,compare # E :
+        subq    modulus,divisor,tmp1    # E :
+
+#ifdef DIV
+        DIV_ONLY(cmovne compare,tmp2,quotient)  # E : Latency 2, extra map slot
+        nop                             # E : as part of the cmovne
+        srl     divisor,1,divisor       # U :
+        nop                             # E : L U L U
+
+        nop                             # E :
+        cmovne  compare,tmp1,modulus    # E : Latency 2, extra map slot
+        nop                             # E : as part of the cmovne
+        bne     mask,2b                 # U : U L U L
+#else
+        srl     divisor,1,divisor       # U :
+        cmovne  compare,tmp1,modulus    # E : Latency 2, extra map slot
+        nop                             # E : as part of the cmovne
+        bne     mask,2b                 # U : U L L U
+#endif
+
+9:      ldq     $1, 0($30)              # L :
+        ldq     $2, 8($30)              # L :
+        nop                             # E :
+        nop                             # E : U U L L
+
+        ldq     $0,16($30)              # L :
+        ldq     tmp1,24($30)            # L :
+        nop                             # E :
+        nop                             # E :
+
+#ifdef DIV
+        DIV_ONLY(ldq tmp2,32($30))      # L :
+#else
+        nop                             # E :
+#endif
+        addq    $30,STACK,$30           # E :
+        ret     $31,($23),1             # L0 : L U U L
+        .end    ufunction
+
+/*
+ * Uhh.. Ugly signed division. I'd rather not have it at all, but
+ * it's needed in some circumstances. There are different ways to
+ * handle this, really. This does:
+ *      -a / b = a / -b = -(a / b)
+ *      -a % b = -(a % b)
+ *      a % -b = a % b
+ * which is probably not the best solution, but at least should
+ * have the property that (x/y)*y + (x%y) = x.
+ */
+.align 4
+.globl  sfunction
+.ent    sfunction
+sfunction:
+        subq    $30,STACK,$30           # E :
+        .frame  $30,STACK,$23
+        .prologue 0
+        bis     $24,$25,$28             # E :
+        SLONGIFY($28)                   # E :
+        bge     $28,7b                  # U :
+
+        stq     $24,0($30)              # L :
+        subq    $31,$24,$28             # E :
+        stq     $25,8($30)              # L :
+        nop                             # E : U L U L
+
+        cmovlt  $24,$28,$24     /* abs($24) */ # E : Latency 2, extra map slot
+        nop                             # E : as part of the cmov
+        stq     $23,16($30)             # L :
+        subq    $31,$25,$28             # E : U L U L
+
+        stq     tmp1,24($30)            # L :
+        cmovlt  $25,$28,$25     /* abs($25) */ # E : Latency 2, extra map slot
+        nop                             # E :
+        bsr     $23,ufunction           # L0: L U L U
+
+        ldq     $24,0($30)              # L :
+        ldq     $25,8($30)              # L :
+        GETSIGN($28)                    # E :
+        subq    $31,$27,tmp1            # E : U U L L
+
+        SLONGIFY($28)                   # E :
+        ldq     $23,16($30)             # L :
+        cmovlt  $28,tmp1,$27            # E : Latency 2, extra map slot
+        nop                             # E : U L L U : as part of the cmov
+
+        ldq     tmp1,24($30)            # L :
+        nop                             # E : as part of the cmov
+        addq    $30,STACK,$30           # E :
+        ret     $31,($23),1             # L0 : L U U L
+        .end    sfunction