import from SF CVS

git-svn-id: https://svn.musicpd.org/mpd/trunk@1 09075e82-0dd4-0310-85a5-a0d7c8717e4f

1 files changed, 1000 insertions, 0 deletions

diff --git a/src/libmad/imdct_l_arm.S b/src/libmad/imdct_l_arm.S
new file mode 100644
index 000000000..963792831
--- /dev/null
+++ b/src/libmad/imdct_l_arm.S
@@ -0,0 +1,1000 @@
+/*****************************************************************************
+* Copyright (C) 2000-2001 Andre McCurdy  <armccurdy@yahoo.co.uk>
+*
+* This program is free software. you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation@ either version 2 of the License, or
+* (at your option) any later version.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY, without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program@ if not, write to the Free Software
+* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*
+*****************************************************************************
+*
+* Notes:
+*
+*
+*****************************************************************************
+*
+* $Id: imdct_l_arm.S,v 1.1 2003/08/14 03:57:13 shank Exp $
+*
+* 2001/03/24:  Andre McCurdy <armccurdy@yahoo.co.uk>
+*   - Corrected PIC unsafe loading of address of 'imdct36_long_karray'
+*
+* 2000/09/20:  Robert Leslie <rob@mars.org>
+*   - Added a global symbol with leading underscore per suggestion of
+*     Simon Burge to support linking with the a.out format.
+*
+* 2000/09/15:  Robert Leslie <rob@mars.org>
+*   - Fixed a small bug where flags were changed before a conditional branch.
+*
+* 2000/09/15:  Andre McCurdy <armccurdy@yahoo.co.uk>
+*   - Applied Nicolas Pitre's rounding optimisation in all remaining places.
+*
+* 2000/09/09:  Nicolas Pitre <nico@cam.org>
+*   - Optimized rounding + scaling operations.
+*
+* 2000/08/09:  Andre McCurdy <armccurdy@yahoo.co.uk>
+*   - Original created.
+*
+****************************************************************************/
+
+
+/*
+   On entry:
+
+      r0 = pointer to 18 element input  array
+      r1 = pointer to 36 element output array
+      r2 = windowing block type
+
+
+   Stack frame created during execution of the function:
+
+   Initial   Holds:
+   Stack
+   pointer
+   minus:
+
+       0
+       4     lr
+       8     r11
+      12     r10
+      16     r9
+      20     r8
+      24     r7
+      28     r6
+      32     r5
+      36     r4
+
+      40     r2 : windowing block type
+
+      44     ct00 high
+      48     ct00 low
+      52     ct01 high
+      56     ct01 low
+      60     ct04 high
+      64     ct04 low
+      68     ct06 high
+      72     ct06 low
+      76     ct05 high
+      80     ct05 low
+      84     ct03 high
+      88     ct03 low
+      92    -ct05 high
+      96    -ct05 low
+     100    -ct07 high
+     104    -ct07 low
+     108     ct07 high
+     112     ct07 low
+     116     ct02 high
+     120     ct02 low
+*/
+
+#define BLOCK_MODE_NORMAL   0
+#define BLOCK_MODE_START    1
+#define BLOCK_MODE_STOP     3
+
+
+#define X0   0x00
+#define X1   0x04
+#define X2   0x08
+#define X3   0x0C
+#define X4   0x10
+#define X5   0x14
+#define X6   0x18
+#define X7   0x1c
+#define X8   0x20
+#define X9   0x24
+#define X10  0x28
+#define X11  0x2c
+#define X12  0x30
+#define X13  0x34
+#define X14  0x38
+#define X15  0x3c
+#define X16  0x40
+#define X17  0x44
+
+#define x0   0x00
+#define x1   0x04
+#define x2   0x08
+#define x3   0x0C
+#define x4   0x10
+#define x5   0x14
+#define x6   0x18
+#define x7   0x1c
+#define x8   0x20
+#define x9   0x24
+#define x10  0x28
+#define x11  0x2c
+#define x12  0x30
+#define x13  0x34
+#define x14  0x38
+#define x15  0x3c
+#define x16  0x40
+#define x17  0x44
+#define x18  0x48
+#define x19  0x4c
+#define x20  0x50
+#define x21  0x54
+#define x22  0x58
+#define x23  0x5c
+#define x24  0x60
+#define x25  0x64
+#define x26  0x68
+#define x27  0x6c
+#define x28  0x70
+#define x29  0x74
+#define x30  0x78
+#define x31  0x7c
+#define x32  0x80
+#define x33  0x84
+#define x34  0x88
+#define x35  0x8c
+
+#define K00  0x0ffc19fd
+#define K01  0x00b2aa3e
+#define K02  0x0fdcf549
+#define K03  0x0216a2a2
+#define K04  0x0f9ee890
+#define K05  0x03768962
+#define K06  0x0f426cb5
+#define K07  0x04cfb0e2
+#define K08  0x0ec835e8
+#define K09  0x061f78aa
+#define K10  0x0e313245
+#define K11  0x07635284
+#define K12  0x0d7e8807
+#define K13  0x0898c779
+#define K14  0x0cb19346
+#define K15  0x09bd7ca0
+#define K16  0x0bcbe352
+#define K17  0x0acf37ad
+
+#define minus_K02 0xf0230ab7
+
+#define WL0  0x00b2aa3e
+#define WL1  0x0216a2a2
+#define WL2  0x03768962
+#define WL3  0x04cfb0e2
+#define WL4  0x061f78aa
+#define WL5  0x07635284
+#define WL6  0x0898c779
+#define WL7  0x09bd7ca0
+#define WL8  0x0acf37ad
+#define WL9  0x0bcbe352
+#define WL10 0x0cb19346
+#define WL11 0x0d7e8807
+#define WL12 0x0e313245
+#define WL13 0x0ec835e8
+#define WL14 0x0f426cb5
+#define WL15 0x0f9ee890
+#define WL16 0x0fdcf549
+#define WL17 0x0ffc19fd
+
+
+@*****************************************************************************
+
+
+    .text
+    .align
+
+    .global III_imdct_l
+    .global _III_imdct_l
+
+III_imdct_l:
+_III_imdct_l:
+
+    stmdb   sp!, { r2, r4 - r11, lr }   @ all callee saved regs, plus arg3
+
+    ldr     r4, =K08                    @ r4 =  K08
+    ldr     r5, =K09                    @ r5 =  K09
+    ldr     r8, [r0, #X4]               @ r8 =  X4
+    ldr     r9, [r0, #X13]              @ r9 =  X13
+    rsb     r6, r4, #0                  @ r6 = -K08
+    rsb     r7, r5, #0                  @ r7 = -K09
+
+    smull   r2, r3, r4, r8              @ r2..r3  = (X4 * K08)
+    smlal   r2, r3, r5, r9              @ r2..r3  = (X4 * K08) + (X13 *  K09) = ct01
+
+    smull   r10, lr, r8, r5             @ r10..lr = (X4 * K09)
+    smlal   r10, lr, r9, r6             @ r10..lr = (X4 * K09) + (X13 * -K08) = ct00
+
+    ldr     r8, [r0, #X7]               @ r8 = X7
+    ldr     r9, [r0, #X16]              @ r9 = X16
+
+    stmdb   sp!, { r2, r3, r10, lr }    @ stack ct00_h, ct00_l, ct01_h, ct01_l
+
+    add     r8, r8, r9                  @ r8 = (X7 + X16)
+    ldr     r9, [r0, #X1]               @ r9 = X1
+
+    smlal   r2, r3, r6, r8              @ r2..r3  = ct01 + ((X7 + X16) * -K08)
+    smlal   r2, r3, r7, r9              @ r2..r3 += (X1  * -K09)
+
+    ldr     r7, [r0, #X10]              @ r7 = X10
+
+    rsbs    r10, r10, #0
+    rsc     lr, lr, #0                  @ r10..lr  = -ct00
+
+    smlal   r2, r3, r5, r7              @ r2..r3  += (X10 *  K09) = ct06
+
+    smlal   r10, lr, r9, r6             @ r10..lr  = -ct00 + ( X1        * -K08)
+    smlal   r10, lr, r8, r5             @ r10..lr +=         ((X7 + X16) *  K09)
+    smlal   r10, lr, r7, r4             @ r10..lr +=         ( X10       *  K08) = ct04
+
+    stmdb   sp!, { r2, r3, r10, lr }    @ stack ct04_h, ct04_l, ct06_h, ct06_l
+
+    @----
+
+    ldr     r7, [r0, #X0]
+    ldr     r8, [r0, #X11]
+    ldr     r9, [r0, #X12]
+    sub     r7, r7, r8
+    sub     r7, r7, r9                  @ r7 = (X0 - X11 -X12) = ct14
+
+    ldr     r9,  [r0, #X3]
+    ldr     r8,  [r0, #X8]
+    ldr     r11, [r0, #X15]
+    sub     r8, r8, r9
+    add     r8, r8, r11                 @ r8 = (X8 - X3 + X15) = ct16
+
+    add     r11, r7, r8                 @ r11 = ct14 + ct16 = ct18
+
+    smlal   r2, r3, r6, r11             @ r2..r3 = ct06 + ((X0 - X11 - X3 + X15 + X8 - X12) * -K08)
+
+    ldr     r6,  [r0, #X2]
+    ldr     r9,  [r0, #X9]
+    ldr     r12, [r0, #X14]
+    sub     r6, r6, r9
+    sub     r6, r6, r12                 @ r6 = (X2 - X9 - X14) = ct15
+
+    ldr     r9,  [r0, #X5]
+    ldr     r12, [r0, #X6]
+    sub     r9, r9, r12
+    ldr     r12, [r0, #X17]
+    sub     r9, r9, r12                 @ r9 = (X5 - X6 - X17) = ct17
+
+    add     r12, r9, r6                 @ r12 = ct15 + ct17 = ct19
+
+    smlal   r2, r3, r5, r12             @ r2..r3 += ((X2 - X9 + X5 - X6 - X17 - X14) * K09)
+
+    smlal   r10, lr, r11, r5            @ r10..lr = ct04 + (ct18 * K09)
+    smlal   r10, lr, r12, r4            @ r10..lr = ct04 + (ct18 * K09) + (ct19 * K08)
+
+    movs    r2, r2, lsr #28
+    adc     r2, r2, r3, lsl #4          @ r2 = bits[59..28] of r2..r3
+    str     r2, [r1, #x22]              @ store result x22
+
+    movs    r10, r10, lsr #28
+    adc     r10, r10, lr, lsl #4        @ r10 = bits[59..28] of r10..lr
+    str     r10, [r1, #x4]              @ store result x4
+
+    @----
+
+    ldmia   sp, { r2, r3, r4, r5 }      @ r2..r3 = ct06, r4..r5 = ct04 (dont update sp)
+
+    @ r2..r3 = ct06
+    @ r4..r5 = ct04
+    @ r6     = ct15
+    @ r7     = ct14
+    @ r8     = ct16
+    @ r9     = ct17
+    @ r10    = .
+    @ r11    = .
+    @ r12    = .
+    @ lr     = .
+
+    ldr     r10, =K03                   @ r10 = K03
+    ldr     lr,  =K15                   @ lr  = K15
+
+    smlal   r2, r3, r10, r7             @ r2..r3 = ct06 + (ct14 * K03)
+    smlal   r4, r5,  lr, r7             @ r4..r5 = ct04 + (ct14 * K15)
+
+    ldr     r12, =K14                   @ r12 =  K14
+    rsb     r10, r10, #0                @ r10 = -K03
+
+    smlal   r2, r3,  lr, r6             @ r2..r3 += (ct15 *  K15)
+    smlal   r4, r5, r10, r6             @ r4..r5 += (ct15 * -K03)
+    smlal   r2, r3, r12, r8             @ r2..r3 += (ct16 *  K14)
+
+    ldr     r11, =minus_K02             @ r11 = -K02
+    rsb     r12, r12, #0                @ r12 = -K14
+
+    smlal   r4, r5, r12, r9             @ r4..r5 += (ct17 * -K14)
+    smlal   r2, r3, r11, r9             @ r2..r3 += (ct17 * -K02)
+    smlal   r4, r5, r11, r8             @ r4..r5 += (ct16 * -K02)
+
+    movs    r2, r2, lsr #28
+    adc     r2, r2, r3, lsl #4          @ r2 = bits[59..28] of r2..r3
+    str     r2, [r1, #x7]               @ store result x7
+
+    movs    r4, r4, lsr #28
+    adc     r4, r4, r5, lsl #4          @ r4 = bits[59..28] of r4..r5
+    str     r4, [r1, #x1]               @ store result x1
+
+    @----
+
+    ldmia   sp, { r2, r3, r4, r5 }      @ r2..r3 = ct06, r4..r5 = ct04 (dont update sp)
+
+    @ r2..r3 = ct06
+    @ r4..r5 = ct04
+    @ r6     = ct15
+    @ r7     = ct14
+    @ r8     = ct16
+    @ r9     = ct17
+    @ r10    = -K03
+    @ r11    = -K02
+    @ r12    = -K14
+    @ lr     =  K15
+
+    rsbs    r2, r2, #0
+    rsc     r3, r3, #0                  @ r2..r3 = -ct06
+
+    smlal   r2, r3, r12, r7             @ r2..r3  = -ct06 + (ct14 * -K14)
+    smlal   r2, r3, r10, r8             @ r2..r3 += (ct16 * -K03)
+
+    smlal   r4, r5, r12, r6             @ r4..r5  =  ct04 + (ct15 * -K14)
+    smlal   r4, r5, r10, r9             @ r4..r5 += (ct17 * -K03)
+    smlal   r4, r5,  lr, r8             @ r4..r5 += (ct16 *  K15)
+    smlal   r4, r5, r11, r7             @ r4..r5 += (ct14 * -K02)
+
+    rsb     lr, lr, #0                  @ lr  = -K15
+    rsb     r11, r11, #0                @ r11 =  K02
+
+    smlal   r2, r3,  lr, r9             @ r2..r3 += (ct17 * -K15)
+    smlal   r2, r3, r11, r6             @ r2..r3 += (ct15 *  K02)
+
+    movs    r4, r4, lsr #28
+    adc     r4, r4, r5, lsl #4          @ r4 = bits[59..28] of r4..r5
+    str     r4, [r1, #x25]              @ store result x25
+
+    movs    r2, r2, lsr #28
+    adc     r2, r2, r3, lsl #4          @ r2 = bits[59..28] of r2..r3
+    str     r2, [r1, #x19]              @ store result x19
+
+    @----
+
+    ldr     r2, [sp, #16]               @ r2 = ct01_l
+    ldr     r3, [sp, #20]               @ r3 = ct01_h
+
+    ldr     r6, [r0, #X1]
+    ldr     r8, [r0, #X7]
+    ldr     r9, [r0, #X10]
+    ldr     r7, [r0, #X16]
+
+    rsbs    r2, r2, #0
+    rsc     r3, r3, #0                  @ r2..r3 = -ct01
+
+    mov     r4, r2
+    mov     r5, r3                      @ r4..r5 = -ct01
+
+    @ r2..r3 = -ct01
+    @ r4..r5 = -ct01
+    @ r6     =  X1
+    @ r7     =  X16
+    @ r8     =  X7
+    @ r9     =  X10
+    @ r10    = -K03
+    @ r11    =  K02
+    @ r12    = -K14
+    @ lr     = -K15
+
+    smlal   r4, r5, r12, r7             @ r4..r5 = -ct01 + (X16 * -K14)
+    smlal   r2, r3,  lr, r9             @ r2..r3 = -ct01 + (X10 * -K15)
+
+    smlal   r4, r5, r10, r8             @ r4..r5 += (X7  * -K03)
+    smlal   r2, r3, r10, r7             @ r2..r3 += (X16 * -K03)
+
+    smlal   r4, r5, r11, r9             @ r4..r5 += (X10 *  K02)
+    smlal   r2, r3, r12, r8             @ r2..r3 += (X7  * -K14)
+
+    rsb     lr, lr, #0                  @ lr  =  K15
+    rsb     r11, r11, #0                @ r11 = -K02
+
+    smlal   r4, r5,  lr, r6             @ r4..r5 += (X1  *  K15) = ct05
+    smlal   r2, r3, r11, r6             @ r2..r3 += (X1  * -K02) = ct03
+
+    stmdb   sp!, { r2, r3, r4, r5 }     @ stack ct05_h, ct05_l, ct03_h, ct03_l
+
+    rsbs    r4, r4, #0
+    rsc     r5, r5, #0                  @ r4..r5 = -ct05
+
+    stmdb   sp!, { r4, r5 }             @ stack -ct05_h, -ct05_l
+
+    ldr     r2, [sp, #48]               @ r2 = ct00_l
+    ldr     r3, [sp, #52]               @ r3 = ct00_h
+
+    rsb     r10, r10, #0                @ r10 = K03
+
+    rsbs    r4, r2, #0
+    rsc     r5, r3, #0                  @ r4..r5 = -ct00
+
+    @ r2..r3 =  ct00
+    @ r4..r5 = -ct00
+    @ r6     =  X1
+    @ r7     =  X16
+    @ r8     =  X7
+    @ r9     =  X10
+    @ r10    =  K03
+    @ r11    = -K02
+    @ r12    = -K14
+    @ lr     =  K15
+
+    smlal   r4, r5, r10, r6             @ r4..r5 = -ct00 + (X1  * K03)
+    smlal   r2, r3, r10, r9             @ r2..r3 =  ct00 + (X10 * K03)
+
+    smlal   r4, r5, r12, r9             @ r4..r5 += (X10 * -K14)
+    smlal   r2, r3, r12, r6             @ r2..r3 += (X1  * -K14)
+
+    smlal   r4, r5, r11, r7             @ r4..r5 += (X16 * -K02)
+    smlal   r4, r5,  lr, r8             @ r4..r5 += (X7  *  K15) = ct07
+
+    rsb     lr, lr, #0                  @ lr  = -K15
+    rsb     r11, r11, #0                @ r11 =  K02
+
+    smlal   r2, r3, r11, r8             @ r2..r3 += (X7  *  K02)
+    smlal   r2, r3,  lr, r7             @ r2..r3 += (X16 * -K15) = ct02
+
+    rsbs    r6, r4, #0
+    rsc     r7, r5, #0                  @ r6..r7 = -ct07
+
+    stmdb   sp!, { r2 - r7 }            @ stack -ct07_h, -ct07_l, ct07_h, ct07_l, ct02_h, ct02_l
+
+
+    @----
+
+    add     r2, pc, #(imdct36_long_karray-.-8)  @ r2 = base address of Knn array (PIC safe ?)
+
+
+loop:
+    ldr     r12, [r0, #X0]
+
+    ldmia   r2!, { r5 - r11 }           @ first 7 words from Karray element
+
+    smull   r3, r4, r5, r12             @ sum =  (Kxx * X0)
+    ldr     r12, [r0, #X2]
+    ldr     r5,  [r0, #X3]
+    smlal   r3, r4, r6, r12             @ sum += (Kxx * X2)
+    ldr     r12, [r0, #X5]
+    ldr     r6,  [r0, #X6]
+    smlal   r3, r4, r7, r5              @ sum += (Kxx * X3)
+    smlal   r3, r4, r8, r12             @ sum += (Kxx * X5)
+    ldr     r12, [r0, #X8]
+    ldr     r5,  [r0, #X9]
+    smlal   r3, r4, r9, r6              @ sum += (Kxx * X6)
+    smlal   r3, r4, r10, r12            @ sum += (Kxx * X8)
+    smlal   r3, r4, r11, r5             @ sum += (Kxx * X9)
+
+    ldmia   r2!, { r5 - r10 }           @ final 6 words from Karray element
+
+    ldr     r11, [r0, #X11]
+    ldr     r12, [r0, #X12]
+    smlal   r3, r4, r5, r11             @ sum += (Kxx * X11)
+    ldr     r11, [r0, #X14]
+    ldr     r5,  [r0, #X15]
+    smlal   r3, r4, r6, r12             @ sum += (Kxx * X12)
+    smlal   r3, r4, r7, r11             @ sum += (Kxx * X14)
+    ldr     r11, [r0, #X17]
+    smlal   r3, r4, r8, r5              @ sum += (Kxx * X15)
+    smlal   r3, r4, r9, r11             @ sum += (Kxx * X17)
+
+    add     r5, sp, r10, lsr #16        @ create index back into stack for required ctxx
+
+    ldmia   r5, { r6, r7 }              @ r6..r7 = ctxx
+
+    mov     r8, r10, lsl #16            @ push ctxx index off the top end
+
+    adds    r3, r3, r6                  @ add low words
+    adc     r4, r4, r7                  @ add high words, with carry
+    movs    r3, r3, lsr #28
+    adc     r3, r3, r4, lsl #4          @ r3 = bits[59..28] of r3..r4
+
+    str     r3, [r1, r8, lsr #24]       @ push completion flag off the bottom end
+
+    movs    r8, r8, lsl #8              @ push result location index off the top end
+    beq     loop                        @ loop back if completion flag not set
+    b       imdct_l_windowing           @ branch to windowing stage if looping finished
+
+imdct36_long_karray:
+
+    .word   K17, -K13,  K10, -K06, -K05,  K01, -K00,  K04, -K07,  K11,  K12, -K16, 0x00000000
+    .word   K13,  K07,  K16,  K01,  K10, -K05,  K04, -K11,  K00, -K17,  K06, -K12, 0x00200800
+    .word   K11,  K17,  K05,  K12, -K01,  K06, -K07,  K00, -K13,  K04, -K16,  K10, 0x00200c00
+    .word   K07,  K00, -K12,  K05, -K16, -K10,  K11, -K17,  K04,  K13,  K01,  K06, 0x00001400
+    .word   K05,  K10, -K00, -K17,  K07, -K13,  K12,  K06, -K16,  K01, -K11, -K04, 0x00181800
+    .word   K01,  K05, -K07, -K11,  K13,  K17, -K16, -K12,  K10,  K06, -K04, -K00, 0x00102000
+    .word  -K16,  K12, -K11,  K07,  K04, -K00, -K01,  K05, -K06,  K10,  K13, -K17, 0x00284800
+    .word  -K12,  K06,  K17, -K00, -K11,  K04,  K05, -K10,  K01,  K16, -K07, -K13, 0x00085000
+    .word  -K10,  K16,  K04, -K13, -K00,  K07,  K06, -K01, -K12, -K05,  K17,  K11, 0x00105400
+    .word  -K06, -K01,  K13,  K04,  K17, -K11, -K10, -K16, -K05,  K12,  K00,  K07, 0x00185c00
+    .word  -K04, -K11, -K01,  K16,  K06,  K12,  K13, -K07, -K17, -K00, -K10, -K05, 0x00006000
+    .word  -K00, -K04, -K06, -K10, -K12, -K16, -K17, -K13, -K11, -K07, -K05, -K01, 0x00206801
+
+
+    @----
+    @-------------------------------------------------------------------------
+    @----
+
+imdct_l_windowing:
+
+    ldr     r11, [sp, #80]              @ fetch function parameter 3 from out of the stack
+    ldmia   r1!, { r0, r2 - r9 }        @ load 9 words from x0, update pointer
+
+    @ r0     = x0
+    @ r1     = &x[9]
+    @ r2     = x1
+    @ r3     = x2
+    @ r4     = x3
+    @ r5     = x4
+    @ r6     = x5
+    @ r7     = x6
+    @ r8     = x7
+    @ r9     = x8
+    @ r10    = .
+    @ r11    = window mode: (0 == normal), (1 == start block), (3 == stop block)
+    @ r12    = .
+    @ lr     = .
+
+    cmp     r11, #BLOCK_MODE_STOP       @ setup flags
+    rsb     r10, r0, #0                 @ r10 = -x0 (DONT change flags !!)
+    beq     stop_block_x0_to_x17
+
+
+    @ start and normal blocks are treated the same for x[0]..x[17]
+
+normal_block_x0_to_x17:
+
+    ldr     r12, =WL9                   @ r12 = window_l[9]
+
+    rsb     r0,  r9, #0                 @ r0  = -x8
+    rsb     r9,  r2, #0                 @ r9  = -x1
+    rsb     r2,  r8, #0                 @ r2  = -x7
+    rsb     r8,  r3, #0                 @ r8  = -x2
+    rsb     r3,  r7, #0                 @ r3  = -x6
+    rsb     r7,  r4, #0                 @ r7  = -x3
+    rsb     r4,  r6, #0                 @ r4  = -x5
+    rsb     r6,  r5, #0                 @ r6  = -x4
+
+    @ r0     = -x8
+    @ r1     = &x[9]
+    @ r2     = -x7
+    @ r3     = -x6
+    @ r4     = -x5
+    @ r5     = .
+    @ r6     = -x4
+    @ r7     = -x3
+    @ r8     = -x2
+    @ r9     = -x1
+    @ r10    = -x0
+    @ r11    = window mode: (0 == normal), (1 == start block), (3 == stop block)
+    @ r12    = window_l[9]
+    @ lr     = .
+
+    smull   r5, lr, r12, r0             @ r5..lr = (window_l[9]  * (x[9]  == -x[8]))
+    ldr     r12, =WL10                  @ r12 = window_l[10]
+    movs    r5, r5, lsr #28
+    adc     r0, r5, lr, lsl #4          @ r0 = bits[59..28] of windowed x9
+
+    smull   r5, lr, r12, r2             @ r5..lr = (window_l[10] * (x[10] == -x[7]))
+    ldr     r12, =WL11                  @ r12 = window_l[11]
+    movs    r5, r5, lsr #28
+    adc     r2, r5, lr, lsl #4          @ r2 = bits[59..28] of windowed x10
+
+    smull   r5, lr, r12, r3             @ r5..lr = (window_l[11] * (x[11] == -x[6]))
+    ldr     r12, =WL12                  @ r12 = window_l[12]
+    movs    r5, r5, lsr #28
+    adc     r3, r5, lr, lsl #4          @ r3 = bits[59..28] of windowed x11
+
+    smull   r5, lr, r12, r4             @ r5..lr = (window_l[12] * (x[12] == -x[5]))
+    ldr     r12, =WL13                  @ r12 = window_l[13]
+    movs    r5, r5, lsr #28
+    adc     r4, r5, lr, lsl #4          @ r4 = bits[59..28] of windowed x12
+
+    smull   r5, lr, r12, r6             @ r5..lr = (window_l[13] * (x[13] == -x[4]))
+    ldr     r12, =WL14                  @ r12 = window_l[14]
+    movs    r5, r5, lsr #28
+    adc     r6, r5, lr, lsl #4          @ r6 = bits[59..28] of windowed x13
+
+    smull   r5, lr, r12, r7             @ r5..lr = (window_l[14] * (x[14] == -x[3]))
+    ldr     r12, =WL15                  @ r12 = window_l[15]
+    movs    r5, r5, lsr #28
+    adc     r7, r5, lr, lsl #4          @ r7 = bits[59..28] of windowed x14
+
+    smull   r5, lr, r12, r8             @ r5..lr = (window_l[15] * (x[15] == -x[2]))
+    ldr     r12, =WL16                  @ r12 = window_l[16]
+    movs    r5, r5, lsr #28
+    adc     r8, r5, lr, lsl #4          @ r8 = bits[59..28] of windowed x15
+
+    smull   r5, lr, r12, r9             @ r5..lr = (window_l[16] * (x[16] == -x[1]))
+    ldr     r12, =WL17                  @ r12 = window_l[17]
+    movs    r5, r5, lsr #28
+    adc     r9, r5, lr, lsl #4          @ r9 = bits[59..28] of windowed x16
+
+    smull   r5, lr, r12, r10            @ r5..lr = (window_l[17] * (x[17] == -x[0]))
+    ldr     r12, =WL0                   @ r12 = window_l[0]
+    movs    r5, r5, lsr #28
+    adc     r10, r5, lr, lsl #4         @ r10 = bits[59..28] of windowed x17
+
+
+    stmia   r1,  { r0, r2 - r4, r6 - r10 } @ store windowed x[9] .. x[17]
+    ldmdb   r1!, { r0, r2 - r9 }           @ load 9 words downto (and including) x0
+
+
+    smull   r10, lr, r12, r0            @ r10..lr = (window_l[0] * x[0])
+    ldr     r12, =WL1                   @ r12 = window_l[1]
+    movs    r10, r10, lsr #28
+    adc     r0, r10, lr, lsl #4         @ r0 = bits[59..28] of windowed x0
+
+    smull   r10, lr, r12, r2            @ r10..lr = (window_l[1] * x[1])
+    ldr     r12, =WL2                   @ r12 = window_l[2]
+    movs    r10, r10, lsr #28
+    adc     r2, r10, lr, lsl #4         @ r2 = bits[59..28] of windowed x1
+
+    smull   r10, lr, r12, r3            @ r10..lr = (window_l[2] * x[2])
+    ldr     r12, =WL3                   @ r12 = window_l[3]
+    movs    r10, r10, lsr #28
+    adc     r3, r10, lr, lsl #4         @ r3 = bits[59..28] of windowed x2
+
+    smull   r10, lr, r12, r4            @ r10..lr = (window_l[3] * x[3])
+    ldr     r12, =WL4                   @ r12 = window_l[4]
+    movs    r10, r10, lsr #28
+    adc     r4, r10, lr, lsl #4         @ r4 = bits[59..28] of windowed x3
+
+    smull   r10, lr, r12, r5            @ r10..lr = (window_l[4] * x[4])
+    ldr     r12, =WL5                   @ r12 = window_l[5]
+    movs    r10, r10, lsr #28
+    adc     r5, r10, lr, lsl #4         @ r5 = bits[59..28] of windowed x4
+
+    smull   r10, lr, r12, r6            @ r10..lr = (window_l[5] * x[5])
+    ldr     r12, =WL6                   @ r12 = window_l[6]
+    movs    r10, r10, lsr #28
+    adc     r6, r10, lr, lsl #4         @ r6 = bits[59..28] of windowed x5
+
+    smull   r10, lr, r12, r7            @ r10..lr = (window_l[6] * x[6])
+    ldr     r12, =WL7                   @ r12 = window_l[7]
+    movs    r10, r10, lsr #28
+    adc     r7, r10, lr, lsl #4         @ r7 = bits[59..28] of windowed x6
+
+    smull   r10, lr, r12, r8            @ r10..lr = (window_l[7] * x[7])
+    ldr     r12, =WL8                   @ r12 = window_l[8]
+    movs    r10, r10, lsr #28
+    adc     r8, r10, lr, lsl #4         @ r8 = bits[59..28] of windowed x7
+
+    smull   r10, lr, r12, r9            @ r10..lr = (window_l[8] * x[8])
+    movs    r10, r10, lsr #28
+    adc     r9, r10, lr, lsl #4         @ r9 = bits[59..28] of windowed x8
+
+    stmia   r1, { r0, r2 - r9 }         @ store windowed x[0] .. x[8]
+
+    cmp     r11, #BLOCK_MODE_START
+    beq     start_block_x18_to_x35
+
+
+    @----
+
+
+normal_block_x18_to_x35:
+
+    ldr     r11, =WL3                   @ r11 = window_l[3]
+    ldr     r12, =WL4                   @ r12 = window_l[4]
+
+    add     r1, r1, #(18*4)             @ r1 = &x[18]
+
+    ldmia   r1!, { r0, r2 - r4, r6 - r10 }  @ load 9 words from x18, update pointer
+
+    @ r0     = x18
+    @ r1     = &x[27]
+    @ r2     = x19
+    @ r3     = x20
+    @ r4     = x21
+    @ r5     = .
+    @ r6     = x22
+    @ r7     = x23
+    @ r8     = x24
+    @ r9     = x25
+    @ r10    = x26
+    @ r11    = window_l[3]
+    @ r12    = window_l[4]
+    @ lr     = .
+
+    smull   r5, lr, r12, r6             @ r5..lr = (window_l[4] * (x[22] == x[31]))
+    movs    r5, r5, lsr #28
+    adc     r5, r5, lr, lsl #4          @ r5 = bits[59..28] of windowed x31
+
+    smull   r6, lr, r11, r4             @ r5..lr = (window_l[3] * (x[21] == x[32]))
+    ldr     r12, =WL5                   @ r12    =  window_l[5]
+    movs    r6, r6, lsr #28
+    adc     r6, r6, lr, lsl #4          @ r6 = bits[59..28] of windowed x32
+
+    smull   r4, lr, r12, r7             @ r4..lr = (window_l[5] * (x[23] == x[30]))
+    ldr     r11, =WL1                   @ r11    =  window_l[1]
+    ldr     r12, =WL2                   @ r12    =  window_l[2]
+    movs    r4, r4, lsr #28
+    adc     r4, r4, lr, lsl #4          @ r4 = bits[59..28] of windowed x30
+
+    smull   r7, lr, r12, r3             @ r7..lr = (window_l[2] * (x[20] == x[33]))
+    ldr     r12, =WL6                   @ r12 = window_l[6]
+    movs    r7, r7, lsr #28
+    adc     r7, r7, lr, lsl #4          @ r7 = bits[59..28] of windowed x33
+
+    smull   r3, lr, r12, r8             @ r3..lr = (window_l[6] * (x[24] == x[29]))
+    movs    r3, r3, lsr #28
+    adc     r3, r3, lr, lsl #4          @ r3 = bits[59..28] of windowed x29
+
+    smull   r8, lr, r11, r2             @ r7..lr = (window_l[1] * (x[19] == x[34]))
+    ldr     r12, =WL7                   @ r12    =  window_l[7]
+    ldr     r11, =WL8                   @ r11    =  window_l[8]
+    movs    r8, r8, lsr #28
+    adc     r8, r8, lr, lsl #4          @ r8 = bits[59..28] of windowed x34
+
+    smull   r2, lr, r12, r9             @ r7..lr = (window_l[7] * (x[25] == x[28]))
+    ldr     r12, =WL0                   @ r12 = window_l[0]
+    movs    r2, r2, lsr #28
+    adc     r2, r2, lr, lsl #4          @ r2 = bits[59..28] of windowed x28
+
+    smull   r9, lr, r12, r0             @ r3..lr = (window_l[0] * (x[18] == x[35]))
+    movs    r9, r9, lsr #28
+    adc     r9, r9, lr, lsl #4          @ r9 = bits[59..28] of windowed x35
+
+    smull   r0, lr, r11, r10            @ r7..lr = (window_l[8] * (x[26] == x[27]))
+    ldr     r11, =WL16                  @ r11    =  window_l[16]
+    ldr     r12, =WL17                  @ r12    =  window_l[17]
+    movs    r0, r0, lsr #28
+    adc     r0, r0, lr, lsl #4          @ r0 = bits[59..28] of windowed x27
+
+
+    stmia   r1,  { r0, r2 - r9 }        @ store windowed x[27] .. x[35]
+    ldmdb   r1!, { r0, r2 - r9 }        @ load 9 words downto (and including) x18
+
+
+    smull   r10, lr, r12, r0            @ r10..lr = (window_l[17] * x[18])
+    movs    r10, r10, lsr #28
+    adc     r0,  r10, lr, lsl #4        @ r0 = bits[59..28] of windowed x0
+
+    smull   r10, lr, r11, r2            @ r10..lr = (window_l[16] * x[19])
+    ldr     r11, =WL14                  @ r11     =  window_l[14]
+    ldr     r12, =WL15                  @ r12     =  window_l[15]
+    movs    r10, r10, lsr #28
+    adc     r2,  r10, lr, lsl #4        @ r2 = bits[59..28] of windowed x1
+
+    smull   r10, lr, r12, r3            @ r10..lr = (window_l[15] * x[20])
+    movs    r10, r10, lsr #28
+    adc     r3,  r10, lr, lsl #4        @ r3 = bits[59..28] of windowed x2
+
+    smull   r10, lr, r11, r4            @ r10..lr = (window_l[14] * x[21])
+    ldr     r11, =WL12                  @ r11     =  window_l[12]
+    ldr     r12, =WL13                  @ r12     =  window_l[13]
+    movs    r10, r10, lsr #28
+    adc     r4,  r10, lr, lsl #4        @ r4 = bits[59..28] of windowed x3
+
+    smull   r10, lr, r12, r5            @ r10..lr = (window_l[13] * x[22])
+    movs    r10, r10, lsr #28
+    adc     r5,  r10, lr, lsl #4        @ r5 = bits[59..28] of windowed x4
+
+    smull   r10, lr, r11, r6            @ r10..lr = (window_l[12] * x[23])
+    ldr     r11, =WL10                  @ r12 = window_l[10]
+    ldr     r12, =WL11                  @ r12 = window_l[11]
+    movs    r10, r10, lsr #28
+    adc     r6,  r10, lr, lsl #4        @ r6 = bits[59..28] of windowed x5
+
+    smull   r10, lr, r12, r7            @ r10..lr = (window_l[11] * x[24])
+    movs    r10, r10, lsr #28
+    adc     r7,  r10, lr, lsl #4        @ r7 = bits[59..28] of windowed x6
+
+    smull   r10, lr, r11, r8            @ r10..lr = (window_l[10] * x[25])
+    ldr     r12, =WL9                   @ r12 = window_l[9]
+    movs    r10, r10, lsr #28
+    adc     r8,  r10, lr, lsl #4        @ r8 = bits[59..28] of windowed x7
+
+    smull   r10, lr, r12, r9            @ r10..lr = (window_l[9] * x[26])
+
+    movs    r10, r10, lsr #28
+    adc     r9,  r10, lr, lsl #4        @ r9 = bits[59..28] of windowed x8
+
+    stmia   r1, { r0, r2 - r9 }         @ store windowed x[18] .. x[26]
+
+    @----
+    @ NB there are 2 possible exits from this function - this is only one of them
+    @----
+
+    add     sp, sp, #(21*4)             @ return stack frame
+    ldmia   sp!, { r4 - r11, pc }       @ restore callee saved regs, and return
+
+    @----
+
+
+stop_block_x0_to_x17:
+
+    @ r0     =  x0
+    @ r1     = &x[9]
+    @ r2     =  x1
+    @ r3     =  x2
+    @ r4     =  x3
+    @ r5     =  x4
+    @ r6     =  x5
+    @ r7     =  x6
+    @ r8     =  x7
+    @ r9     =  x8
+    @ r10    = -x0
+    @ r11    =  window mode: (0 == normal), (1 == start block), (3 == stop block)
+    @ r12    =  .
+    @ lr     =  .
+
+    rsb     r0, r6, #0                  @ r0 = -x5
+    rsb     r6, r2, #0                  @ r6 = -x1
+    rsb     r2, r5, #0                  @ r2 = -x4
+    rsb     r5, r3, #0                  @ r5 = -x2
+    rsb     r3, r4, #0                  @ r3 = -x3
+
+    add     r1, r1, #(3*4)                      @ r1 = &x[12]
+    stmia   r1, { r0, r2, r3, r5, r6, r10 }     @ store unchanged x[12] .. x[17]
+
+    ldr     r0, =WL1                    @ r0 = window_l[1]  == window_s[0]
+
+    rsb     r10, r9, #0                 @ r10 = -x8
+    rsb     r12, r8, #0                 @ r12 = -x7
+    rsb     lr,  r7, #0                 @ lr  = -x6
+
+    @ r0     =  WL1
+    @ r1     = &x[12]
+    @ r2     =  .
+    @ r3     =  .
+    @ r4     =  .
+    @ r5     =  .
+    @ r6     =  .
+    @ r7     =  x6
+    @ r8     =  x7
+    @ r9     =  x8
+    @ r10    = -x8
+    @ r11    =  window mode: (0 == normal), (1 == start block), (3 == stop block)
+    @ r12    = -x7
+    @ lr     = -x6
+
+    smull   r5, r6, r0, r7              @ r5..r6 = (window_l[1] * x[6])
+    ldr     r2, =WL4                    @ r2     =  window_l[4] == window_s[1]
+    movs    r5, r5, lsr #28
+    adc     r7, r5, r6, lsl #4          @ r7 = bits[59..28] of windowed x6
+
+    smull   r5, r6, r2, r8              @ r5..r6 = (window_l[4] * x[7])
+    ldr     r3, =WL7                    @ r3     =  window_l[7] == window_s[2]
+    movs    r5, r5, lsr #28
+    adc     r8, r5, r6, lsl #4          @ r8 = bits[59..28] of windowed x7
+
+    smull   r5, r6, r3, r9              @ r5..r6 = (window_l[7] * x[8])
+    ldr     r4, =WL10                   @ r4     =  window_l[10] == window_s[3]
+    movs    r5, r5, lsr #28
+    adc     r9, r5, r6, lsl #4          @ r9 = bits[59..28] of windowed x8
+
+    smull   r5, r6, r4, r10             @ r5..r6 = (window_l[10] * (x[9] == -x[8]))
+    ldr     r0, =WL13                   @ r0     =  window_l[13] == window_s[4]
+    movs    r5, r5, lsr #28
+    adc     r10, r5, r6, lsl #4         @ r10 = bits[59..28] of windowed x9
+
+    smull   r5, r6, r0, r12             @ r5..r6 = (window_l[13] * (x[10] == -x[7]))
+    ldr     r2, =WL16                   @ r2     =  window_l[16] == window_s[5]
+    movs    r5, r5, lsr #28
+    adc     r12, r5, r6, lsl #4         @ r10 = bits[59..28] of windowed x9
+
+    smull   r5, r6, r2, lr              @ r5..r6 = (window_l[16] * (x[11] == -x[6]))
+
+    ldr     r0, =0x00
+
+    movs    r5, r5, lsr #28
+    adc     lr, r5, r6, lsl #4          @ r10 = bits[59..28] of windowed x9
+
+    stmdb   r1!, { r7 - r10, r12, lr }  @ store windowed x[6] .. x[11]
+
+    ldr     r5, =0x00
+    ldr     r6, =0x00
+    ldr     r2, =0x00
+    ldr     r3, =0x00
+    ldr     r4, =0x00
+
+    stmdb   r1!, { r0, r2 - r6 }        @ store windowed x[0] .. x[5]
+
+    b       normal_block_x18_to_x35
+
+
+    @----
+
+
+start_block_x18_to_x35:
+
+    ldr     r4, =WL1                    @ r0 = window_l[1]  == window_s[0]
+
+    add     r1, r1, #(24*4)             @ r1 = &x[24]
+
+    ldmia   r1, { r0, r2, r3 }          @ load 3 words from x24, dont update pointer
+
+    @ r0     = x24
+    @ r1     = &x[24]
+    @ r2     = x25
+    @ r3     = x26
+    @ r4     = WL1
+    @ r5     = WL4
+    @ r6     = WL7
+    @ r7     = WL10
+    @ r8     = WL13
+    @ r9     = WL16
+    @ r10    = .
+    @ r11    = .
+    @ r12    = .
+    @ lr     = .
+
+    ldr     r5, =WL4                    @ r5 = window_l[4] == window_s[1]
+
+    smull   r10, r11, r4, r0            @ r10..r11 = (window_l[1] * (x[24] == x[29]))
+    ldr     r6, =WL7                    @ r6       =  window_l[7]  == window_s[2]
+    movs    r10, r10, lsr #28
+    adc     lr, r10, r11, lsl #4        @ lr = bits[59..28] of windowed x29
+
+    smull   r10, r11, r5, r2            @ r10..r11 = (window_l[4] * (x[25] == x[28]))
+    ldr     r7, =WL10                   @ r7       =  window_l[10] == window_s[3]
+    movs    r10, r10, lsr #28
+    adc     r12, r10, r11, lsl #4       @ r12 = bits[59..28] of windowed x28
+
+    smull   r10, r11, r6, r3            @ r10..r11 = (window_l[7] * (x[26] == x[27]))
+    ldr     r8, =WL13                   @ r8       =  window_l[13] == window_s[4]
+    movs    r10, r10, lsr #28
+    adc     r4, r10, r11, lsl #4        @ r4 = bits[59..28] of windowed x27
+
+    smull   r10, r11, r7, r3            @ r10..r11 = (window_l[10] * x[26])
+    ldr     r9, =WL16                   @ r9       =  window_l[16] == window_s[5]
+    movs    r10, r10, lsr #28
+    adc     r3, r10, r11, lsl #4        @ r3 = bits[59..28] of windowed x26
+
+    smull   r10, r11, r8, r2            @ r10..r11 = (window_l[13] * x[25])
+    ldr     r5, =0x00
+    movs    r10, r10, lsr #28
+    adc     r2, r10, r11, lsl #4        @ r2 = bits[59..28] of windowed x25
+
+    smull   r10, r11, r9, r0            @ r10..r11 = (window_l[16] * x[24])
+    ldr     r6, =0x00
+    movs    r10, r10, lsr #28
+    adc     r0, r10, r11, lsl #4        @ r0 = bits[59..28] of windowed x24
+
+    stmia   r1!, { r0, r2, r3, r4, r12, lr }    @ store windowed x[24] .. x[29]
+
+    ldr     r7, =0x00
+    ldr     r8, =0x00
+    ldr     r9, =0x00
+    ldr     r10, =0x00
+
+    stmia   r1!, { r5 - r10 }           @ store windowed x[30] .. x[35]
+
+    @----
+    @ NB there are 2 possible exits from this function - this is only one of them
+    @----
+
+    add     sp, sp, #(21*4)             @ return stack frame
+    ldmia   sp!, { r4 - r11, pc }       @ restore callee saved regs, and return
+
+    @----
+    @END
+    @----
+