projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* |
| 2 | * Optmized version of the ip_fast_csum() function | |
| 3 | * Used for calculating IP header checksum | |
| 4 | * | |
| 5 | * Return: 16bit checksum, complemented | |
| 6 | * | |
| 7 | * Inputs: | |
| 8 | * in0: address of buffer to checksum (char *) | |
| 9 | * in1: length of the buffer (int) | |
| 10 | * | |
| 007d77d0 CK |
11 | * Copyright (C) 2002, 2006 Intel Corp. |
| 12 | * Copyright (C) 2002, 2006 Ken Chen <kenneth.w.chen@intel.com> | |
| 1da177e4 LT |
13 | */ |
| 14 | ||
| 15 | #include <asm/asmmacro.h> | |
| 16 | ||
| 17 | /* | |
| 18 | * Since we know that most likely this function is called with buf aligned | |
| 19 | * on 4-byte boundary and 20 bytes in length, we can execution rather quickly | |
| 20 | * versus calling generic version of do_csum, which has lots of overhead in | |
| 21 | * handling various alignments and sizes. However, due to lack of constrains | |
| 22 | * put on the function input argument, cases with alignment not on 4-byte or | |
| 23 | * size not equal to 20 bytes will be handled by the generic do_csum function. | |
| 24 | */ | |
| 25 | ||
| 26 | #define in0 r32 | |
| 27 | #define in1 r33 | |
| 007d77d0 CK |
28 | #define in2 r34 |
| 29 | #define in3 r35 | |
| 30 | #define in4 r36 | |
| 1da177e4 LT |
31 | #define ret0 r8 |
| 32 | ||
| 33 | GLOBAL_ENTRY(ip_fast_csum) | |
| 34 | .prologue | |
| 35 | .body | |
| 36 | cmp.ne p6,p7=5,in1 // size other than 20 byte? | |
| 37 | and r14=3,in0 // is it aligned on 4-byte? | |
| 38 | add r15=4,in0 // second source pointer | |
| 39 | ;; | |
| 40 | cmp.ne.or.andcm p6,p7=r14,r0 | |
| 41 | ;; | |
| 42 | (p7) ld4 r20=[in0],8 | |
| 43 | (p7) ld4 r21=[r15],8 | |
| 44 | (p6) br.spnt .generic | |
| 45 | ;; | |
| 46 | ld4 r22=[in0],8 | |
| 47 | ld4 r23=[r15],8 | |
| 48 | ;; | |
| 49 | ld4 r24=[in0] | |
| 50 | add r20=r20,r21 | |
| 51 | add r22=r22,r23 | |
| 52 | ;; | |
| 53 | add r20=r20,r22 | |
| 54 | ;; | |
| 55 | add r20=r20,r24 | |
| 56 | ;; | |
| 57 | shr.u ret0=r20,16 // now need to add the carry | |
| 58 | zxt2 r20=r20 | |
| 59 | ;; | |
| 60 | add r20=ret0,r20 | |
| 61 | ;; | |
| 62 | shr.u ret0=r20,16 // add carry again | |
| 63 | zxt2 r20=r20 | |
| 64 | ;; | |
| 65 | add r20=ret0,r20 | |
| 66 | ;; | |
| 67 | shr.u ret0=r20,16 | |
| 68 | zxt2 r20=r20 | |
| 69 | ;; | |
| 70 | add r20=ret0,r20 | |
| 6dbfc19b | 71 | mov r9=0xffff |
| 1da177e4 | 72 | ;; |
| 6dbfc19b | 73 | andcm ret0=r9,r20 |
| 1da177e4 LT |
74 | .restore sp // reset frame state |
| 75 | br.ret.sptk.many b0 | |
| 76 | ;; | |
| 77 | ||
| 78 | .generic: | |
| 79 | .prologue | |
| 80 | .save ar.pfs, r35 | |
| 81 | alloc r35=ar.pfs,2,2,2,0 | |
| 82 | .save rp, r34 | |
| 83 | mov r34=b0 | |
| 84 | .body | |
| 85 | dep.z out1=in1,2,30 | |
| 86 | mov out0=in0 | |
| 87 | ;; | |
| 88 | br.call.sptk.many b0=do_csum | |
| 89 | ;; | |
| 90 | andcm ret0=-1,ret0 | |
| 91 | mov ar.pfs=r35 | |
| 92 | mov b0=r34 | |
| 93 | br.ret.sptk.many b0 | |
| 94 | END(ip_fast_csum) | |
| 007d77d0 CK |
95 | |
| 96 | GLOBAL_ENTRY(csum_ipv6_magic) | |
| 97 | ld4 r20=[in0],4 | |
| 98 | ld4 r21=[in1],4 | |
| 99 | dep r15=in3,in2,32,16 | |
| 100 | ;; | |
| 101 | ld4 r22=[in0],4 | |
| 102 | ld4 r23=[in1],4 | |
| 103 | mux1 r15=r15,@rev | |
| 104 | ;; | |
| 105 | ld4 r24=[in0],4 | |
| 106 | ld4 r25=[in1],4 | |
| 107 | shr.u r15=r15,16 | |
| 108 | add r16=r20,r21 | |
| 109 | add r17=r22,r23 | |
| 110 | ;; | |
| 111 | ld4 r26=[in0],4 | |
| 112 | ld4 r27=[in1],4 | |
| 113 | add r18=r24,r25 | |
| 114 | add r8=r16,r17 | |
| 115 | ;; | |
| 116 | add r19=r26,r27 | |
| 117 | add r8=r8,r18 | |
| 118 | ;; | |
| 119 | add r8=r8,r19 | |
| 120 | add r15=r15,in4 | |
| 121 | ;; | |
| 122 | add r8=r8,r15 | |
| 123 | ;; | |
| 124 | shr.u r10=r8,32 // now fold sum into short | |
| 125 | zxt4 r11=r8 | |
| 126 | ;; | |
| 127 | add r8=r10,r11 | |
| 128 | ;; | |
| 129 | shr.u r10=r8,16 // yeah, keep it rolling | |
| 130 | zxt2 r11=r8 | |
| 131 | ;; | |
| 132 | add r8=r10,r11 | |
| 133 | ;; | |
| 134 | shr.u r10=r8,16 // three times lucky | |
| 135 | zxt2 r11=r8 | |
| 136 | ;; | |
| 137 | add r8=r10,r11 | |
| 138 | mov r9=0xffff | |
| 139 | ;; | |
| 140 | andcm r8=r9,r8 | |
| 141 | br.ret.sptk.many b0 | |
| 142 | END(csum_ipv6_magic) |