arch/arm/lib/io-readsb.S

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  *  linux/arch/arm/lib/io-readsb.S
   4  *
   5  *  Copyright (C) 1995-2000 Russell King
   6  */
   7 #include <linux/linkage.h>
   8 #include <asm/assembler.h>
   9
  10 .Linsb_align:   rsb     ip, ip, #4
  11                 cmp     ip, r2
  12                 movgt   ip, r2
  13                 cmp     ip, #2
  14                 ldrb    r3, [r0]
  15                 strb    r3, [r1], #1
  16                 ldrbge  r3, [r0]
  17                 strbge  r3, [r1], #1
  18                 ldrbgt  r3, [r0]
  19                 strbgt  r3, [r1], #1
  20                 subs    r2, r2, ip
  21                 bne     .Linsb_aligned
  22
  23 ENTRY(__raw_readsb)
  24                 teq     r2, #0          @ do we have to check for the zero len?
  25                 reteq   lr
  26                 ands    ip, r1, #3
  27                 bne     .Linsb_align
  28
  29 .Linsb_aligned: stmfd   sp!, {r4 - r6, lr}
  30
  31                 subs    r2, r2, #16
  32                 bmi     .Linsb_no_16
  33
  34 .Linsb_16_lp:   ldrb    r3, [r0]
  35                 ldrb    r4, [r0]
  36                 ldrb    r5, [r0]
  37                 mov     r3, r3,     put_byte_0
  38                 ldrb    r6, [r0]
  39                 orr     r3, r3, r4, put_byte_1
  40                 ldrb    r4, [r0]
  41                 orr     r3, r3, r5, put_byte_2
  42                 ldrb    r5, [r0]
  43                 orr     r3, r3, r6, put_byte_3
  44                 ldrb    r6, [r0]
  45                 mov     r4, r4,     put_byte_0
  46                 ldrb    ip, [r0]
  47                 orr     r4, r4, r5, put_byte_1
  48                 ldrb    r5, [r0]
  49                 orr     r4, r4, r6, put_byte_2
  50                 ldrb    r6, [r0]
  51                 orr     r4, r4, ip, put_byte_3
  52                 ldrb    ip, [r0]
  53                 mov     r5, r5,     put_byte_0
  54                 ldrb    lr, [r0]
  55                 orr     r5, r5, r6, put_byte_1
  56                 ldrb    r6, [r0]
  57                 orr     r5, r5, ip, put_byte_2
  58                 ldrb    ip, [r0]
  59                 orr     r5, r5, lr, put_byte_3
  60                 ldrb    lr, [r0]
  61                 mov     r6, r6,     put_byte_0
  62                 orr     r6, r6, ip, put_byte_1
  63                 ldrb    ip, [r0]
  64                 orr     r6, r6, lr, put_byte_2
  65                 orr     r6, r6, ip, put_byte_3
  66                 stmia   r1!, {r3 - r6}
  67
  68                 subs    r2, r2, #16
  69                 bpl     .Linsb_16_lp
  70
  71                 tst     r2, #15
  72                 ldmfdeq sp!, {r4 - r6, pc}
  73
  74 .Linsb_no_16:   tst     r2, #8
  75                 beq     .Linsb_no_8
  76
  77                 ldrb    r3, [r0]
  78                 ldrb    r4, [r0]
  79                 ldrb    r5, [r0]
  80                 mov     r3, r3,     put_byte_0
  81                 ldrb    r6, [r0]
  82                 orr     r3, r3, r4, put_byte_1
  83                 ldrb    r4, [r0]
  84                 orr     r3, r3, r5, put_byte_2
  85                 ldrb    r5, [r0]
  86                 orr     r3, r3, r6, put_byte_3
  87                 ldrb    r6, [r0]
  88                 mov     r4, r4,     put_byte_0
  89                 ldrb    ip, [r0]
  90                 orr     r4, r4, r5, put_byte_1
  91                 orr     r4, r4, r6, put_byte_2
  92                 orr     r4, r4, ip, put_byte_3
  93                 stmia   r1!, {r3, r4}
  94
  95 .Linsb_no_8:    tst     r2, #4
  96                 beq     .Linsb_no_4
  97
  98                 ldrb    r3, [r0]
  99                 ldrb    r4, [r0]
 100                 ldrb    r5, [r0]
 101                 ldrb    r6, [r0]
 102                 mov     r3, r3,     put_byte_0
 103                 orr     r3, r3, r4, put_byte_1
 104                 orr     r3, r3, r5, put_byte_2
 105                 orr     r3, r3, r6, put_byte_3
 106                 str     r3, [r1], #4
 107
 108 .Linsb_no_4:    ands    r2, r2, #3
 109                 ldmfdeq sp!, {r4 - r6, pc}
 110
 111                 cmp     r2, #2
 112                 ldrb    r3, [r0]
 113                 strb    r3, [r1], #1
 114                 ldrbge  r3, [r0]
 115                 strbge  r3, [r1], #1
 116                 ldrbgt  r3, [r0]
 117                 strbgt  r3, [r1]
 118
 119                 ldmfd   sp!, {r4 - r6, pc}
 120 ENDPROC(__raw_readsb)