/*
   * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
   *
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 and
   * only version 2 as published by the Free Software Foundation.
   *
   * 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., 51 Franklin Street, Fifth Floor, Boston, MA
   * 02110-1301, USA.
   */
  
  /*
   * Description
   *
   *   library function for memcpy where length bytes are copied from
   *   ptr_in to ptr_out. ptr_out is returned unchanged.
   *   Allows any combination of alignment on input and output pointers
   *   and length from 0 to 2^32-1
   *
   * Restrictions
   *   The arrays should not overlap, the program will produce undefined output
   *   if they do.
   *   For blocks less than 16 bytes a byte by byte copy is performed. For
   *   8byte alignments, and length multiples, a dword copy is performed up to
   *   96bytes
   * History
   *
   *   DJH  5/15/09 Initial version 1.0
   *   DJH  6/ 1/09 Version 1.1 modified ABI to inlcude R16-R19
   *   DJH  7/12/09 Version 1.2 optimized codesize down to 760 was 840
   *   DJH 10/14/09 Version 1.3 added special loop for aligned case, was
   *                            overreading bloated codesize back up to 892
   *   DJH  4/20/10 Version 1.4 fixed Ldword_loop_epilog loop to prevent loads
   *                            occuring if only 1 left outstanding, fixes bug
   *                            # 3888, corrected for all alignments. Peeled off
   *                            1 32byte chunk from kernel loop and extended 8byte
   *                            loop at end to solve all combinations and prevent
   *                            over read.  Fixed Ldword_loop_prolog to prevent
   *                            overread for blocks less than 48bytes. Reduced
   *                            codesize to 752 bytes
   *   DJH  4/21/10 version 1.5 1.4 fix broke code for input block ends not
   *                            aligned to dword boundaries,underwriting by 1
   *                            byte, added detection for this and fixed. A
   *                            little bloat.
   *   DJH  4/23/10 version 1.6 corrected stack error, R20 was not being restored
   *                            always, fixed the error of R20 being modified
   *                            before it was being saved
   * Natural c model
   * ===============
   * void * memcpy(char * ptr_out, char * ptr_in, int length) {
   *   int i;
   *   if(length) for(i=0; i < length; i++) { ptr_out[i] = ptr_in[i]; }
   *   return(ptr_out);
   * }
   *
   * Optimized memcpy function
   * =========================
   * void * memcpy(char * ptr_out, char * ptr_in, int len) {
   *   int i, prolog, kernel, epilog, mask;
   *   u8 offset;
   *   s64 data0, dataF8, data70;
   *
   *   s64 * ptr8_in;
   *   s64 * ptr8_out;
   *   s32 * ptr4;
   *   s16 * ptr2;
   *
   *   offset = ((int) ptr_in) & 7;
   *   ptr8_in = (s64 *) &ptr_in[-offset];   //read in the aligned pointers
   *
   *   data70 = *ptr8_in++;
   *   dataF8 = *ptr8_in++;
   *
   *   data0 = HEXAGON_P_valignb_PPp(dataF8, data70, offset);
   *
   *   prolog = 32 - ((int) ptr_out);
   *   mask  = 0x7fffffff >> HEXAGON_R_cl0_R(len);
   *   prolog = prolog & mask;
   *   kernel = len - prolog;
   *   epilog = kernel & 0x1F;
   *   kernel = kernel>>5;
   *
   *   if (prolog & 1) { ptr_out[0] = (u8) data0; data0 >>= 8; ptr_out += 1;}
   *   ptr2 = (s16 *) &ptr_out[0];
   *   if (prolog & 2) { ptr2[0] = (u16) data0;  data0 >>= 16; ptr_out += 2;}
   *   ptr4 = (s32 *) &ptr_out[0];
   *   if (prolog & 4) { ptr4[0] = (u32) data0;  data0 >>= 32; ptr_out += 4;}
   *
   *   offset = offset + (prolog & 7);
   *   if (offset >= 8) {
   *     data70 = dataF8;
   *     dataF8 = *ptr8_in++;
   *   }
   *   offset = offset & 0x7;
   *
   *   prolog = prolog >> 3;
   *   if (prolog) for (i=0; i < prolog; i++) {
   *       data0 = HEXAGON_P_valignb_PPp(dataF8, data70, offset);
   *       ptr8_out = (s64 *) &ptr_out[0]; *ptr8_out = data0; ptr_out += 8;
   *       data70 = dataF8;
   *       dataF8 = *ptr8_in++;
   *   }
   *   if(kernel) { kernel -= 1; epilog += 32; }
   *   if(kernel) for(i=0; i < kernel; i++) {
   *       data0 = HEXAGON_P_valignb_PPp(dataF8, data70, offset);
   *       ptr8_out = (s64 *) &ptr_out[0]; *ptr8_out = data0; ptr_out += 8;
   *       data70 = *ptr8_in++;
   *
   *       data0 = HEXAGON_P_valignb_PPp(data70, dataF8, offset);
   *       ptr8_out = (s64 *) &ptr_out[0]; *ptr8_out = data0; ptr_out += 8;
   *       dataF8 = *ptr8_in++;
   *
   *       data0 = HEXAGON_P_valignb_PPp(dataF8, data70, offset);
   *       ptr8_out = (s64 *) &ptr_out[0]; *ptr8_out = data0; ptr_out += 8;
   *       data70 = *ptr8_in++;
   *
   *       data0 = HEXAGON_P_valignb_PPp(data70, dataF8, offset);
   *       ptr8_out = (s64 *) &ptr_out[0]; *ptr8_out = data0; ptr_out += 8;
   *       dataF8 = *ptr8_in++;
   *   }
   *   epilogdws = epilog >> 3;
   *   if (epilogdws) for (i=0; i < epilogdws; i++) {
   *       data0 = HEXAGON_P_valignb_PPp(dataF8, data70, offset);
   *       ptr8_out = (s64 *) &ptr_out[0]; *ptr8_out = data0; ptr_out += 8;
   *       data70 = dataF8;
   *       dataF8 = *ptr8_in++;
   *   }
   *   data0 = HEXAGON_P_valignb_PPp(dataF8, data70, offset);
   *
   *   ptr4 = (s32 *) &ptr_out[0];
   *   if (epilog & 4) { ptr4[0] = (u32) data0; data0 >>= 32; ptr_out += 4;}
   *   ptr2 = (s16 *) &ptr_out[0];
   *   if (epilog & 2) { ptr2[0] = (u16) data0; data0 >>= 16; ptr_out += 2;}
   *   if (epilog & 1) { *ptr_out++ = (u8) data0; }
   *
   *   return(ptr_out - length);
   * }
   *
   * Codesize : 784 bytes
   */
  
  
  #define ptr_out		R0	/*  destination  pounter  */
  #define ptr_in		R1	/*  source pointer  */
  #define len		R2	/*  length of copy in bytes  */
  
  #define data70		R13:12	/*  lo 8 bytes of non-aligned transfer  */
  #define dataF8		R11:10	/*  hi 8 bytes of non-aligned transfer  */
  #define ldata0		R7:6	/*  even 8 bytes chunks  */
  #define ldata1		R25:24	/*  odd 8 bytes chunks  */
  #define data1		R7	/*  lower 8 bytes of ldata1  */
  #define data0		R6	/*  lower 8 bytes of ldata0  */
  
  #define ifbyte		p0	/*  if transfer has bytes in epilog/prolog  */
  #define ifhword		p0	/*  if transfer has shorts in epilog/prolog  */
  #define ifword		p0	/*  if transfer has words in epilog/prolog  */
  #define noprolog	p0	/*  no prolog, xfer starts at 32byte  */
  #define nokernel	p1	/*  no 32byte multiple block in the transfer  */
  #define noepilog	p0	/*  no epilog, xfer ends on 32byte boundary  */
  #define align		p2	/*  alignment of input rel to 8byte boundary  */
  #define kernel1		p0	/*  kernel count == 1  */
  
  #define dalign		R25	/*  rel alignment of input to output data  */
  #define star3		R16	/*  number bytes in prolog - dwords  */
  #define rest		R8	/*  length - prolog bytes  */
  #define back		R7	/*  nr bytes > dword boundary in src block  */
  #define epilog		R3	/*  bytes in epilog  */
  #define inc		R15:14	/*  inc kernel by -1 and defetch ptr by 32  */
  #define kernel		R4	/*  number of 32byte chunks in kernel  */
  #define ptr_in_p_128	R5	/*  pointer for prefetch of input data  */
  #define mask		R8	/*  mask used to determine prolog size  */
  #define shift		R8	/*  used to work a shifter to extract bytes  */
  #define shift2		R5	/*  in epilog to workshifter to extract bytes */
  #define prolog		R15	/*  bytes in  prolog  */
  #define epilogdws	R15	/*  number dwords in epilog  */
  #define shiftb		R14	/*  used to extract bytes  */
  #define offset		R9	/*  same as align in reg  */
  #define ptr_out_p_32	R17	/*  pointer to output dczero  */
  #define align888	R14	/*  if simple dword loop can be used  */
  #define len8		R9	/*  number of dwords in length  */
  #define over		R20	/*  nr of bytes > last inp buf dword boundary */
  
  #define ptr_in_p_128kernel	R5:4	/*  packed fetch pointer & kernel cnt */
  
  	.section .text
  	.p2align 4
          .global memcpy
          .type memcpy, @function
  memcpy:
  {
  	p2 = cmp.eq(len, #0);		/*  =0 */
  	align888 = or(ptr_in, ptr_out);	/*  %8 < 97 */
  	p0 = cmp.gtu(len, #23);		/*  %1, <24 */
  	p1 = cmp.eq(ptr_in, ptr_out);	/*  attempt to overwrite self */
  }
  {
  	p1 = or(p2, p1);
  	p3 = cmp.gtu(len, #95);		/*  %8 < 97 */
  	align888 = or(align888, len);	/*  %8 < 97 */
  	len8 = lsr(len, #3);		/*  %8 < 97 */
  }
  {
  	dcfetch(ptr_in);		/*  zero/ptrin=ptrout causes fetch */
  	p2 = bitsclr(align888, #7);	/*  %8 < 97  */
  	if(p1) jumpr r31;		/*  =0  */
  }
  {
  	p2 = and(p2,!p3);			/*  %8 < 97  */
  	if (p2.new) len = add(len, #-8);	/*  %8 < 97  */
  	if (p2.new) jump:NT .Ldwordaligned; 	/*  %8 < 97  */
  }
  {
  	if(!p0) jump .Lbytes23orless;	/*  %1, <24  */
  	mask.l = #LO(0x7fffffff);
  	/*  all bytes before line multiples of data  */
  	prolog = sub(#0, ptr_out);
  }
  {
  	/*  save r31 on stack, decrement sp by 16  */
  	allocframe(#24);
  	mask.h = #HI(0x7fffffff);
  	ptr_in_p_128 = add(ptr_in, #32);
  	back = cl0(len);
  }
  {
  	memd(sp+#0) = R17:16;		/*  save r16,r17 on stack6  */
  	r31.l = #LO(.Lmemcpy_return);	/*  set up final return pointer  */
  	prolog &= lsr(mask, back);
  	offset = and(ptr_in, #7);
  }
  {
  	memd(sp+#8) = R25:24;		/*  save r25,r24 on stack  */
  	dalign = sub(ptr_out, ptr_in);
  	r31.h = #HI(.Lmemcpy_return);	/*  set up final return pointer  */
  }
  {
  	/*  see if there if input buffer end if aligned  */
  	over = add(len, ptr_in);
  	back = add(len, offset);
  	memd(sp+#16) = R21:20;		/*  save r20,r21 on stack  */
  }
  {
  	noprolog = bitsclr(prolog, #7);
  	prolog = and(prolog, #31);
  	dcfetch(ptr_in_p_128);
  	ptr_in_p_128 = add(ptr_in_p_128, #32);
  }
  {
  	kernel = sub(len, prolog);
  	shift = asl(prolog, #3);
  	star3 = and(prolog, #7);
  	ptr_in = and(ptr_in, #-8);
  }
  {
  	prolog = lsr(prolog, #3);
  	epilog = and(kernel, #31);
  	ptr_out_p_32 = add(ptr_out, prolog);
  	over = and(over, #7);
  }
  {
  	p3 = cmp.gtu(back, #8);
  	kernel = lsr(kernel, #5);
  	dcfetch(ptr_in_p_128);
  	ptr_in_p_128 = add(ptr_in_p_128, #32);
  }
  {
  	p1 = cmp.eq(prolog, #0);
  	if(!p1.new) prolog = add(prolog, #1);
  	dcfetch(ptr_in_p_128);	/*  reserve the line 64bytes on  */
  	ptr_in_p_128 = add(ptr_in_p_128, #32);
  }
  {
  	nokernel = cmp.eq(kernel,#0);
  	dcfetch(ptr_in_p_128);	/* reserve the line 64bytes on  */
  	ptr_in_p_128 = add(ptr_in_p_128, #32);
  	shiftb = and(shift, #8);
  }
  {
  	dcfetch(ptr_in_p_128);		/*  reserve the line 64bytes on  */
  	ptr_in_p_128 = add(ptr_in_p_128, #32);
  	if(nokernel) jump .Lskip64;
  	p2 = cmp.eq(kernel, #1);	/*  skip ovr if kernel == 0  */
  }
  {
  	dczeroa(ptr_out_p_32);
  	/*  don't advance pointer  */
  	if(!p2) ptr_out_p_32 = add(ptr_out_p_32, #32);
  }
  {
  	dalign = and(dalign, #31);
  	dczeroa(ptr_out_p_32);
  }
  .Lskip64:
  {
  	data70 = memd(ptr_in++#16);
  	if(p3) dataF8 = memd(ptr_in+#8);
  	if(noprolog) jump .Lnoprolog32;
  	align = offset;
  }
  /*  upto initial 7 bytes  */
  {
  	ldata0 = valignb(dataF8, data70, align);
  	ifbyte = tstbit(shift,#3);
  	offset = add(offset, star3);
  }
  {
  	if(ifbyte) memb(ptr_out++#1) = data0;
  	ldata0 = lsr(ldata0, shiftb);
  	shiftb = and(shift, #16);
  	ifhword = tstbit(shift,#4);
  }
  {
  	if(ifhword) memh(ptr_out++#2) = data0;
  	ldata0 = lsr(ldata0, shiftb);
  	ifword = tstbit(shift,#5);
  	p2 = cmp.gtu(offset, #7);
  }
  {
  	if(ifword) memw(ptr_out++#4) = data0;
  	if(p2) data70 = dataF8;
  	if(p2) dataF8 = memd(ptr_in++#8);	/*  another 8 bytes  */
  	align = offset;
  }
  .Lnoprolog32:
  {
  	p3 = sp1loop0(.Ldword_loop_prolog, prolog)
  	rest = sub(len, star3);	/*  whats left after the loop  */
  	p0 = cmp.gt(over, #0);
  }
  	if(p0) rest = add(rest, #16);
  .Ldword_loop_prolog:
  {
  	if(p3) memd(ptr_out++#8) = ldata0;
  	ldata0 = valignb(dataF8, data70, align);
  	p0 = cmp.gt(rest, #16);
  }
  {
  	data70 = dataF8;
  	if(p0) dataF8 = memd(ptr_in++#8);
  	rest = add(rest, #-8);
  }:endloop0
  .Lkernel:
  {
  	/*  kernel is at least 32bytes  */
  	p3 = cmp.gtu(kernel, #0);
  	/*  last itn. remove edge effects  */
  	if(p3.new) kernel = add(kernel, #-1);
  	/*  dealt with in last dword loop  */
  	if(p3.new) epilog = add(epilog, #32);
  }
  {
  	nokernel = cmp.eq(kernel, #0);		/*  after adjustment, recheck */
  	if(nokernel.new) jump:NT .Lepilog;	/*  likely not taken  */
  	inc = combine(#32, #-1);
  	p3 = cmp.gtu(dalign, #24);
  }
  {
  	if(p3) jump .Lodd_alignment;
  }
  {
  	loop0(.Loword_loop_25to31, kernel);
  	kernel1 = cmp.gtu(kernel, #1);
  	rest = kernel;
  }
  	.falign
  .Loword_loop_25to31:
  {
  	dcfetch(ptr_in_p_128);	/*  prefetch 4 lines ahead  */
  	if(kernel1) ptr_out_p_32 = add(ptr_out_p_32, #32);
  }
  {
  	dczeroa(ptr_out_p_32);	/*  reserve the next 32bytes in cache  */
  	p3 = cmp.eq(kernel, rest);
  }
  {
  	/*  kernel -= 1  */
  	ptr_in_p_128kernel = vaddw(ptr_in_p_128kernel, inc);
  	/*  kill write on first iteration  */
  	if(!p3) memd(ptr_out++#8) = ldata1;
  	ldata1 = valignb(dataF8, data70, align);
  	data70 = memd(ptr_in++#8);
  }
  {
  	memd(ptr_out++#8) = ldata0;
  	ldata0 = valignb(data70, dataF8, align);
  	dataF8 = memd(ptr_in++#8);
  }
  {
  	memd(ptr_out++#8) = ldata1;
  	ldata1 = valignb(dataF8, data70, align);
  	data70 = memd(ptr_in++#8);
  }
  {
  	memd(ptr_out++#8) = ldata0;
  	ldata0 = valignb(data70, dataF8, align);
  	dataF8 = memd(ptr_in++#8);
  	kernel1 = cmp.gtu(kernel, #1);
  }:endloop0
  {
  	memd(ptr_out++#8) = ldata1;
  	jump .Lepilog;
  }
  .Lodd_alignment:
  {
  	loop0(.Loword_loop_00to24, kernel);
  	kernel1 = cmp.gtu(kernel, #1);
  	rest = add(kernel, #-1);
  }
  	.falign
  .Loword_loop_00to24:
  {
  	dcfetch(ptr_in_p_128);	/*  prefetch 4 lines ahead  */
  	ptr_in_p_128kernel = vaddw(ptr_in_p_128kernel, inc);
  	if(kernel1) ptr_out_p_32 = add(ptr_out_p_32, #32);
  }
  {
  	dczeroa(ptr_out_p_32);	/*  reserve the next 32bytes in cache  */
  }
  {
  	memd(ptr_out++#8) = ldata0;
  	ldata0 = valignb(dataF8, data70, align);
  	data70 = memd(ptr_in++#8);
  }
  {
  	memd(ptr_out++#8) = ldata0;
  	ldata0 = valignb(data70, dataF8, align);
  	dataF8 = memd(ptr_in++#8);
  }
  {
  	memd(ptr_out++#8) = ldata0;
  	ldata0 = valignb(dataF8, data70, align);
  	data70 = memd(ptr_in++#8);
  }
  {
  	memd(ptr_out++#8) = ldata0;
  	ldata0 = valignb(data70, dataF8, align);
  	dataF8 = memd(ptr_in++#8);
  	kernel1 = cmp.gtu(kernel, #1);
  }:endloop0
  .Lepilog:
  {
  	noepilog = cmp.eq(epilog,#0);
  	epilogdws = lsr(epilog, #3);
  	kernel = and(epilog, #7);
  }
  {
  	if(noepilog) jumpr r31;
  	if(noepilog) ptr_out = sub(ptr_out, len);
  	p3 = cmp.eq(epilogdws, #0);
  	shift2 = asl(epilog, #3);
  }
  {
  	shiftb = and(shift2, #32);
  	ifword = tstbit(epilog,#2);
  	if(p3) jump .Lepilog60;
  	if(!p3) epilog = add(epilog, #-16);
  }
  {
  	loop0(.Ldword_loop_epilog, epilogdws);
  	/*  stop criteria is lsbs unless = 0 then its 8  */
  	p3 = cmp.eq(kernel, #0);
  	if(p3.new) kernel= #8;
  	p1 = cmp.gt(over, #0);
  }
  	/*  if not aligned to end of buffer execute 1 more iteration  */
  	if(p1) kernel= #0;
  .Ldword_loop_epilog:
  {
  	memd(ptr_out++#8) = ldata0;
  	ldata0 = valignb(dataF8, data70, align);
  	p3 = cmp.gt(epilog, kernel);
  }
  {
  	data70 = dataF8;
  	if(p3) dataF8 = memd(ptr_in++#8);
  	epilog = add(epilog, #-8);
  }:endloop0
  /* copy last 7 bytes */
  .Lepilog60:
  {
  	if(ifword) memw(ptr_out++#4) = data0;
  	ldata0 = lsr(ldata0, shiftb);
  	ifhword = tstbit(epilog,#1);
  	shiftb = and(shift2, #16);
  }
  {
  	if(ifhword) memh(ptr_out++#2) = data0;
  	ldata0 = lsr(ldata0, shiftb);
  	ifbyte = tstbit(epilog,#0);
  	if(ifbyte.new) len = add(len, #-1);
  }
  {
  	if(ifbyte) memb(ptr_out) = data0;
  	ptr_out = sub(ptr_out, len);	/*  return dest pointer  */
          jumpr r31;
  }
  /*  do byte copy for small n  */
  .Lbytes23orless:
  {
  	p3 = sp1loop0(.Lbyte_copy, len);
  	len = add(len, #-1);
  }
  .Lbyte_copy:
  {
  	data0 = memb(ptr_in++#1);
  	if(p3) memb(ptr_out++#1) = data0;
  }:endloop0
  {
  	memb(ptr_out) = data0;
  	ptr_out = sub(ptr_out, len);
  	jumpr r31;
  }
  /*  do dword copies for aligned in, out and length  */
  .Ldwordaligned:
  {
  	p3 = sp1loop0(.Ldword_copy, len8);
  }
  .Ldword_copy:
  {
  	if(p3) memd(ptr_out++#8) = ldata0;
  	ldata0 = memd(ptr_in++#8);
  }:endloop0
  {
  	memd(ptr_out) = ldata0;
  	ptr_out = sub(ptr_out, len);
  	jumpr r31;	/*  return to function caller  */
  }
  .Lmemcpy_return:
  	r21:20 = memd(sp+#16);	/*  restore r20+r21  */
  {
  	r25:24 = memd(sp+#8);	/*  restore r24+r25  */
  	r17:16 = memd(sp+#0);	/*  restore r16+r17  */
  }
  	deallocframe;	/*  restore r31 and incrment stack by 16  */
  	jumpr r31