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, 321 insertions, 0 deletions

diff --git a/arch/alpha/lib/ev6-stxcpy.S b/arch/alpha/lib/ev6-stxcpy.S
new file mode 100644
index 000000000000..4643ff2ffc8d
--- /dev/null
+++ b/arch/alpha/lib/ev6-stxcpy.S
@@ -0,0 +1,321 @@
+/*
+ * arch/alpha/lib/ev6-stxcpy.S
+ * 21264 version contributed by Rick Gorton <rick.gorton@alpha-processor.com>
+ *
+ * Copy a null-terminated string from SRC to DST.
+ *
+ * This is an internal routine used by strcpy, stpcpy, and strcat.
+ * As such, it uses special linkage conventions to make implementation
+ * of these public functions more efficient.
+ *
+ * On input:
+ *      t9 = return address
+ *      a0 = DST
+ *      a1 = SRC
+ *
+ * On output:
+ *      t12 = bitmask (with one bit set) indicating the last byte written
+ *      a0  = unaligned address of the last *word* written
+ *
+ * Furthermore, v0, a3-a5, t11, and t12 are untouched.
+ *
+ * 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.
+ */
+
+#include <asm/regdef.h>
+
+        .set noat
+        .set noreorder
+
+        .text
+
+/* There is a problem with either gdb (as of 4.16) or gas (as of 2.7) that
+   doesn't like putting the entry point for a procedure somewhere in the
+   middle of the procedure descriptor.  Work around this by putting the
+   aligned copy in its own procedure descriptor */
+
+
+        .ent stxcpy_aligned
+        .align 4
+stxcpy_aligned:
+        .frame sp, 0, t9
+        .prologue 0
+
+        /* On entry to this basic block:
+           t0 == the first destination word for masking back in
+           t1 == the first source word.  */
+
+        /* Create the 1st output word and detect 0's in the 1st input word.  */
+        lda     t2, -1          # E : build a mask against false zero
+        mskqh   t2, a1, t2      # U :   detection in the src word (stall)
+        mskqh   t1, a1, t3      # U :
+        ornot   t1, t2, t2      # E : (stall)
+
+        mskql   t0, a1, t0      # U : assemble the first output word
+        cmpbge  zero, t2, t8    # E : bits set iff null found
+        or      t0, t3, t1      # E : (stall)
+        bne     t8, $a_eos      # U : (stall)
+
+        /* On entry to this basic block:
+           t0 == the first destination word for masking back in
+           t1 == a source word not containing a null.  */
+        /* Nops here to separate store quads from load quads */
+
+$a_loop:
+        stq_u   t1, 0(a0)       # L :
+        addq    a0, 8, a0       # E :
+        nop
+        nop
+
+        ldq_u   t1, 0(a1)       # L : Latency=3
+        addq    a1, 8, a1       # E :
+        cmpbge  zero, t1, t8    # E : (3 cycle stall)
+        beq     t8, $a_loop     # U : (stall for t8)
+
+        /* Take care of the final (partial) word store.
+           On entry to this basic block we have:
+           t1 == the source word containing the null
+           t8 == the cmpbge mask that found it.  */
+$a_eos:
+        negq    t8, t6          # E : find low bit set
+        and     t8, t6, t12     # E : (stall)
+        /* For the sake of the cache, don't read a destination word
+           if we're not going to need it.  */
+        and     t12, 0x80, t6   # E : (stall)
+        bne     t6, 1f          # U : (stall)
+
+        /* We're doing a partial word store and so need to combine
+           our source and original destination words.  */
+        ldq_u   t0, 0(a0)       # L : Latency=3
+        subq    t12, 1, t6      # E :
+        zapnot  t1, t6, t1      # U : clear src bytes >= null (stall)
+        or      t12, t6, t8     # E : (stall)
+
+        zap     t0, t8, t0      # E : clear dst bytes <= null
+        or      t0, t1, t1      # E : (stall)
+        nop
+        nop
+
+1:      stq_u   t1, 0(a0)       # L :
+        ret     (t9)            # L0 : Latency=3
+        nop
+        nop
+
+        .end stxcpy_aligned
+
+        .align 4
+        .ent __stxcpy
+        .globl __stxcpy
+__stxcpy:
+        .frame sp, 0, t9
+        .prologue 0
+
+        /* Are source and destination co-aligned?  */
+        xor     a0, a1, t0      # E :
+        unop                    # E :
+        and     t0, 7, t0       # E : (stall)
+        bne     t0, $unaligned  # U : (stall)
+
+        /* We are co-aligned; take care of a partial first word.  */
+        ldq_u   t1, 0(a1)               # L : load first src word
+        and     a0, 7, t0               # E : take care not to load a word ...
+        addq    a1, 8, a1               # E :
+        beq     t0, stxcpy_aligned      # U : ... if we wont need it (stall)
+
+        ldq_u   t0, 0(a0)       # L :
+        br      stxcpy_aligned  # L0 : Latency=3
+        nop
+        nop
+
+
+/* The source and destination are not co-aligned.  Align the destination
+   and cope.  We have to be very careful about not reading too much and
+   causing a SEGV.  */
+
+        .align 4
+$u_head:
+        /* We know just enough now to be able to assemble the first
+           full source word.  We can still find a zero at the end of it
+           that prevents us from outputting the whole thing.
+
+           On entry to this basic block:
+           t0 == the first dest word, for masking back in, if needed else 0
+           t1 == the low bits of the first source word
+           t6 == bytemask that is -1 in dest word bytes */
+
+        ldq_u   t2, 8(a1)       # L :
+        addq    a1, 8, a1       # E :
+        extql   t1, a1, t1      # U : (stall on a1)
+        extqh   t2, a1, t4      # U : (stall on a1)
+
+        mskql   t0, a0, t0      # U :
+        or      t1, t4, t1      # E :
+        mskqh   t1, a0, t1      # U : (stall on t1)
+        or      t0, t1, t1      # E : (stall on t1)
+
+        or      t1, t6, t6      # E :
+        cmpbge  zero, t6, t8    # E : (stall)
+        lda     t6, -1          # E : for masking just below
+        bne     t8, $u_final    # U : (stall)
+
+        mskql   t6, a1, t6              # U : mask out the bits we have
+        or      t6, t2, t2              # E :   already extracted before (stall)
+        cmpbge  zero, t2, t8            # E :   testing eos (stall)
+        bne     t8, $u_late_head_exit   # U : (stall)
+
+        /* Finally, we've got all the stupid leading edge cases taken care
+           of and we can set up to enter the main loop.  */
+
+        stq_u   t1, 0(a0)       # L : store first output word
+        addq    a0, 8, a0       # E :
+        extql   t2, a1, t0      # U : position ho-bits of lo word
+        ldq_u   t2, 8(a1)       # U : read next high-order source word
+
+        addq    a1, 8, a1       # E :
+        cmpbge  zero, t2, t8    # E : (stall for t2)
+        nop                     # E :
+        bne     t8, $u_eos      # U : (stall)
+
+        /* Unaligned copy main loop.  In order to avoid reading too much,
+           the loop is structured to detect zeros in aligned source words.
+           This has, unfortunately, effectively pulled half of a loop
+           iteration out into the head and half into the tail, but it does
+           prevent nastiness from accumulating in the very thing we want
+           to run as fast as possible.
+
+           On entry to this basic block:
+           t0 == the shifted high-order bits from the previous source word
+           t2 == the unshifted current source word
+
+           We further know that t2 does not contain a null terminator.  */
+
+        .align 3
+$u_loop:
+        extqh   t2, a1, t1      # U : extract high bits for current word
+        addq    a1, 8, a1       # E : (stall)
+        extql   t2, a1, t3      # U : extract low bits for next time (stall)
+        addq    a0, 8, a0       # E :
+
+        or      t0, t1, t1      # E : current dst word now complete
+        ldq_u   t2, 0(a1)       # L : Latency=3 load high word for next time
+        stq_u   t1, -8(a0)      # L : save the current word (stall)
+        mov     t3, t0          # E :
+
+        cmpbge  zero, t2, t8    # E : test new word for eos
+        beq     t8, $u_loop     # U : (stall)
+        nop
+        nop
+
+        /* We've found a zero somewhere in the source word we just read.
+           If it resides in the lower half, we have one (probably partial)
+           word to write out, and if it resides in the upper half, we
+           have one full and one partial word left to write out.
+
+           On entry to this basic block:
+           t0 == the shifted high-order bits from the previous source word
+           t2 == the unshifted current source word.  */
+$u_eos:
+        extqh   t2, a1, t1      # U :
+        or      t0, t1, t1      # E : first (partial) source word complete (stall)
+        cmpbge  zero, t1, t8    # E : is the null in this first bit? (stall)
+        bne     t8, $u_final    # U : (stall)
+
+$u_late_head_exit:
+        stq_u   t1, 0(a0)       # L : the null was in the high-order bits
+        addq    a0, 8, a0       # E :
+        extql   t2, a1, t1      # U :
+        cmpbge  zero, t1, t8    # E : (stall)
+
+        /* Take care of a final (probably partial) result word.
+           On entry to this basic block:
+           t1 == assembled source word
+           t8 == cmpbge mask that found the null.  */
+$u_final:
+        negq    t8, t6          # E : isolate low bit set
+        and     t6, t8, t12     # E : (stall)
+        and     t12, 0x80, t6   # E : avoid dest word load if we can (stall)
+        bne     t6, 1f          # U : (stall)
+
+        ldq_u   t0, 0(a0)       # E :
+        subq    t12, 1, t6      # E :
+        or      t6, t12, t8     # E : (stall)
+        zapnot  t1, t6, t1      # U : kill source bytes >= null (stall)
+
+        zap     t0, t8, t0      # U : kill dest bytes <= null (2 cycle data stall)
+        or      t0, t1, t1      # E : (stall)
+        nop
+        nop
+
+1:      stq_u   t1, 0(a0)       # L :
+        ret     (t9)            # L0 : Latency=3
+        nop
+        nop
+
+        /* Unaligned copy entry point.  */
+        .align 4
+$unaligned:
+
+        ldq_u   t1, 0(a1)       # L : load first source word
+        and     a0, 7, t4       # E : find dest misalignment
+        and     a1, 7, t5       # E : find src misalignment
+        /* Conditionally load the first destination word and a bytemask
+           with 0xff indicating that the destination byte is sacrosanct.  */
+        mov     zero, t0        # E :
+
+        mov     zero, t6        # E :
+        beq     t4, 1f          # U :
+        ldq_u   t0, 0(a0)       # L :
+        lda     t6, -1          # E :
+
+        mskql   t6, a0, t6      # U :
+        nop
+        nop
+        nop
+1:
+        subq    a1, t4, a1      # E : sub dest misalignment from src addr
+        /* If source misalignment is larger than dest misalignment, we need
+           extra startup checks to avoid SEGV.  */
+        cmplt   t4, t5, t12     # E :
+        beq     t12, $u_head    # U :
+        lda     t2, -1          # E : mask out leading garbage in source
+
+        mskqh   t2, t5, t2      # U :
+        ornot   t1, t2, t3      # E : (stall)
+        cmpbge  zero, t3, t8    # E : is there a zero? (stall)
+        beq     t8, $u_head     # U : (stall)
+
+        /* At this point we've found a zero in the first partial word of
+           the source.  We need to isolate the valid source data and mask
+           it into the original destination data.  (Incidentally, we know
+           that we'll need at least one byte of that original dest word.) */
+
+        ldq_u   t0, 0(a0)       # L :
+        negq    t8, t6          # E : build bitmask of bytes <= zero
+        and     t6, t8, t12     # E : (stall)
+        and     a1, 7, t5       # E :
+
+        subq    t12, 1, t6      # E :
+        or      t6, t12, t8     # E : (stall)
+        srl     t12, t5, t12    # U : adjust final null return value
+        zapnot  t2, t8, t2      # U : prepare source word; mirror changes (stall)
+
+        and     t1, t2, t1      # E : to source validity mask
+        extql   t2, a1, t2      # U :
+        extql   t1, a1, t1      # U : (stall)
+        andnot  t0, t2, t0      # .. e1 : zero place for source to reside (stall)
+
+        or      t0, t1, t1      # e1    : and put it there
+        stq_u   t1, 0(a0)       # .. e0 : (stall)
+        ret     (t9)            # e1    :
+        nop
+
+        .end __stxcpy
+