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kernel/linux-imx6_3.14.28/arch/arm/lib/csumpartialcopygeneric.S 6.69 KB
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  /*
   *  linux/arch/arm/lib/csumpartialcopygeneric.S
   *
   *  Copyright (C) 1995-2001 Russell King
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  
  /*
   * unsigned int
   * csum_partial_copy_xxx(const char *src, char *dst, int len, int sum, )
   *  r0 = src, r1 = dst, r2 = len, r3 = sum
   *  Returns : r0 = checksum
   *
   * Note that 'tst' and 'teq' preserve the carry flag.
   */
  
  src	.req	r0
  dst	.req	r1
  len	.req	r2
  sum	.req	r3
  
  .Lzero:		mov	r0, sum
  		load_regs
  
  		/*
  		 * Align an unaligned destination pointer.  We know that
  		 * we have >= 8 bytes here, so we don't need to check
  		 * the length.  Note that the source pointer hasn't been
  		 * aligned yet.
  		 */
  .Ldst_unaligned:
  		tst	dst, #1
  		beq	.Ldst_16bit
  
  		load1b	ip
  		sub	len, len, #1
  		adcs	sum, sum, ip, put_byte_1	@ update checksum
  		strb	ip, [dst], #1
  		tst	dst, #2
  		moveq	pc, lr			@ dst is now 32bit aligned
  
  .Ldst_16bit:	load2b	r8, ip
  		sub	len, len, #2
  		adcs	sum, sum, r8, put_byte_0
  		strb	r8, [dst], #1
  		adcs	sum, sum, ip, put_byte_1
  		strb	ip, [dst], #1
  		mov	pc, lr			@ dst is now 32bit aligned
  
  		/*
  		 * Handle 0 to 7 bytes, with any alignment of source and
  		 * destination pointers.  Note that when we get here, C = 0
  		 */
  .Lless8:	teq	len, #0			@ check for zero count
  		beq	.Lzero
  
  		/* we must have at least one byte. */
  		tst	dst, #1			@ dst 16-bit aligned
  		beq	.Lless8_aligned
  
  		/* Align dst */
  		load1b	ip
  		sub	len, len, #1
  		adcs	sum, sum, ip, put_byte_1	@ update checksum
  		strb	ip, [dst], #1
  		tst	len, #6
  		beq	.Lless8_byteonly
  
  1:		load2b	r8, ip
  		sub	len, len, #2
  		adcs	sum, sum, r8, put_byte_0
  		strb	r8, [dst], #1
  		adcs	sum, sum, ip, put_byte_1
  		strb	ip, [dst], #1
  .Lless8_aligned:
  		tst	len, #6
  		bne	1b
  .Lless8_byteonly:
  		tst	len, #1
  		beq	.Ldone
  		load1b	r8
  		adcs	sum, sum, r8, put_byte_0	@ update checksum
  		strb	r8, [dst], #1
  		b	.Ldone
  
  FN_ENTRY
  		save_regs
  
  		cmp	len, #8			@ Ensure that we have at least
  		blo	.Lless8			@ 8 bytes to copy.
  
  		adds	sum, sum, #0		@ C = 0
  		tst	dst, #3			@ Test destination alignment
  		blne	.Ldst_unaligned		@ align destination, return here
  
  		/*
  		 * Ok, the dst pointer is now 32bit aligned, and we know
  		 * that we must have more than 4 bytes to copy.  Note
  		 * that C contains the carry from the dst alignment above.
  		 */
  
  		tst	src, #3			@ Test source alignment
  		bne	.Lsrc_not_aligned
  
  		/* Routine for src & dst aligned */
  
  		bics	ip, len, #15
  		beq	2f
  
  1:		load4l	r4, r5, r6, r7
  		stmia	dst!, {r4, r5, r6, r7}
  		adcs	sum, sum, r4
  		adcs	sum, sum, r5
  		adcs	sum, sum, r6
  		adcs	sum, sum, r7
  		sub	ip, ip, #16
  		teq	ip, #0
  		bne	1b
  
  2:		ands	ip, len, #12
  		beq	4f
  		tst	ip, #8
  		beq	3f
  		load2l	r4, r5
  		stmia	dst!, {r4, r5}
  		adcs	sum, sum, r4
  		adcs	sum, sum, r5
  		tst	ip, #4
  		beq	4f
  
  3:		load1l	r4
  		str	r4, [dst], #4
  		adcs	sum, sum, r4
  
  4:		ands	len, len, #3
  		beq	.Ldone
  		load1l	r4
  		tst	len, #2
  		mov	r5, r4, get_byte_0
  		beq	.Lexit
  		adcs	sum, sum, r4, push #16
  		strb	r5, [dst], #1
  		mov	r5, r4, get_byte_1
  		strb	r5, [dst], #1
  		mov	r5, r4, get_byte_2
  .Lexit:		tst	len, #1
  		strneb	r5, [dst], #1
  		andne	r5, r5, #255
  		adcnes	sum, sum, r5, put_byte_0
  
  		/*
  		 * If the dst pointer was not 16-bit aligned, we
  		 * need to rotate the checksum here to get around
  		 * the inefficient byte manipulations in the
  		 * architecture independent code.
  		 */
  .Ldone:		adc	r0, sum, #0
  		ldr	sum, [sp, #0]		@ dst
  		tst	sum, #1
  		movne	r0, r0, ror #8
  		load_regs
  
  .Lsrc_not_aligned:
  		adc	sum, sum, #0		@ include C from dst alignment
  		and	ip, src, #3
  		bic	src, src, #3
  		load1l	r5
  		cmp	ip, #2
  		beq	.Lsrc2_aligned
  		bhi	.Lsrc3_aligned
  		mov	r4, r5, pull #8		@ C = 0
  		bics	ip, len, #15
  		beq	2f
  1:		load4l	r5, r6, r7, r8
  		orr	r4, r4, r5, push #24
  		mov	r5, r5, pull #8
  		orr	r5, r5, r6, push #24
  		mov	r6, r6, pull #8
  		orr	r6, r6, r7, push #24
  		mov	r7, r7, pull #8
  		orr	r7, r7, r8, push #24
  		stmia	dst!, {r4, r5, r6, r7}
  		adcs	sum, sum, r4
  		adcs	sum, sum, r5
  		adcs	sum, sum, r6
  		adcs	sum, sum, r7
  		mov	r4, r8, pull #8
  		sub	ip, ip, #16
  		teq	ip, #0
  		bne	1b
  2:		ands	ip, len, #12
  		beq	4f
  		tst	ip, #8
  		beq	3f
  		load2l	r5, r6
  		orr	r4, r4, r5, push #24
  		mov	r5, r5, pull #8
  		orr	r5, r5, r6, push #24
  		stmia	dst!, {r4, r5}
  		adcs	sum, sum, r4
  		adcs	sum, sum, r5
  		mov	r4, r6, pull #8
  		tst	ip, #4
  		beq	4f
  3:		load1l	r5
  		orr	r4, r4, r5, push #24
  		str	r4, [dst], #4
  		adcs	sum, sum, r4
  		mov	r4, r5, pull #8
  4:		ands	len, len, #3
  		beq	.Ldone
  		mov	r5, r4, get_byte_0
  		tst	len, #2
  		beq	.Lexit
  		adcs	sum, sum, r4, push #16
  		strb	r5, [dst], #1
  		mov	r5, r4, get_byte_1
  		strb	r5, [dst], #1
  		mov	r5, r4, get_byte_2
  		b	.Lexit
  
  .Lsrc2_aligned:	mov	r4, r5, pull #16
  		adds	sum, sum, #0
  		bics	ip, len, #15
  		beq	2f
  1:		load4l	r5, r6, r7, r8
  		orr	r4, r4, r5, push #16
  		mov	r5, r5, pull #16
  		orr	r5, r5, r6, push #16
  		mov	r6, r6, pull #16
  		orr	r6, r6, r7, push #16
  		mov	r7, r7, pull #16
  		orr	r7, r7, r8, push #16
  		stmia	dst!, {r4, r5, r6, r7}
  		adcs	sum, sum, r4
  		adcs	sum, sum, r5
  		adcs	sum, sum, r6
  		adcs	sum, sum, r7
  		mov	r4, r8, pull #16
  		sub	ip, ip, #16
  		teq	ip, #0
  		bne	1b
  2:		ands	ip, len, #12
  		beq	4f
  		tst	ip, #8
  		beq	3f
  		load2l	r5, r6
  		orr	r4, r4, r5, push #16
  		mov	r5, r5, pull #16
  		orr	r5, r5, r6, push #16
  		stmia	dst!, {r4, r5}
  		adcs	sum, sum, r4
  		adcs	sum, sum, r5
  		mov	r4, r6, pull #16
  		tst	ip, #4
  		beq	4f
  3:		load1l	r5
  		orr	r4, r4, r5, push #16
  		str	r4, [dst], #4
  		adcs	sum, sum, r4
  		mov	r4, r5, pull #16
  4:		ands	len, len, #3
  		beq	.Ldone
  		mov	r5, r4, get_byte_0
  		tst	len, #2
  		beq	.Lexit
  		adcs	sum, sum, r4
  		strb	r5, [dst], #1
  		mov	r5, r4, get_byte_1
  		strb	r5, [dst], #1
  		tst	len, #1
  		beq	.Ldone
  		load1b	r5
  		b	.Lexit
  
  .Lsrc3_aligned:	mov	r4, r5, pull #24
  		adds	sum, sum, #0
  		bics	ip, len, #15
  		beq	2f
  1:		load4l	r5, r6, r7, r8
  		orr	r4, r4, r5, push #8
  		mov	r5, r5, pull #24
  		orr	r5, r5, r6, push #8
  		mov	r6, r6, pull #24
  		orr	r6, r6, r7, push #8
  		mov	r7, r7, pull #24
  		orr	r7, r7, r8, push #8
  		stmia	dst!, {r4, r5, r6, r7}
  		adcs	sum, sum, r4
  		adcs	sum, sum, r5
  		adcs	sum, sum, r6
  		adcs	sum, sum, r7
  		mov	r4, r8, pull #24
  		sub	ip, ip, #16
  		teq	ip, #0
  		bne	1b
  2:		ands	ip, len, #12
  		beq	4f
  		tst	ip, #8
  		beq	3f
  		load2l	r5, r6
  		orr	r4, r4, r5, push #8
  		mov	r5, r5, pull #24
  		orr	r5, r5, r6, push #8
  		stmia	dst!, {r4, r5}
  		adcs	sum, sum, r4
  		adcs	sum, sum, r5
  		mov	r4, r6, pull #24
  		tst	ip, #4
  		beq	4f
  3:		load1l	r5
  		orr	r4, r4, r5, push #8
  		str	r4, [dst], #4
  		adcs	sum, sum, r4
  		mov	r4, r5, pull #24
  4:		ands	len, len, #3
  		beq	.Ldone
  		mov	r5, r4, get_byte_0
  		tst	len, #2
  		beq	.Lexit
  		strb	r5, [dst], #1
  		adcs	sum, sum, r4
  		load1l	r4
  		mov	r5, r4, get_byte_0
  		strb	r5, [dst], #1
  		adcs	sum, sum, r4, push #24
  		mov	r5, r4, get_byte_1
  		b	.Lexit
  FN_EXIT