diff options
Diffstat (limited to 'kernel/arch/ia64/lib/ip_fast_csum.S')
| -rw-r--r-- | kernel/arch/ia64/lib/ip_fast_csum.S | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/kernel/arch/ia64/lib/ip_fast_csum.S b/kernel/arch/ia64/lib/ip_fast_csum.S new file mode 100644 index 000000000..620d9dc52 --- /dev/null +++ b/kernel/arch/ia64/lib/ip_fast_csum.S @@ -0,0 +1,144 @@ +/* + * Optmized version of the ip_fast_csum() function + * Used for calculating IP header checksum + * + * Return: 16bit checksum, complemented + * + * Inputs: + * in0: address of buffer to checksum (char *) + * in1: length of the buffer (int) + * + * Copyright (C) 2002, 2006 Intel Corp. + * Copyright (C) 2002, 2006 Ken Chen <kenneth.w.chen@intel.com> + */ + +#include <asm/asmmacro.h> + +/* + * Since we know that most likely this function is called with buf aligned + * on 4-byte boundary and 20 bytes in length, we can execution rather quickly + * versus calling generic version of do_csum, which has lots of overhead in + * handling various alignments and sizes. However, due to lack of constrains + * put on the function input argument, cases with alignment not on 4-byte or + * size not equal to 20 bytes will be handled by the generic do_csum function. + */ + +#define in0 r32 +#define in1 r33 +#define in2 r34 +#define in3 r35 +#define in4 r36 +#define ret0 r8 + +GLOBAL_ENTRY(ip_fast_csum) + .prologue + .body + cmp.ne p6,p7=5,in1 // size other than 20 byte? + and r14=3,in0 // is it aligned on 4-byte? + add r15=4,in0 // second source pointer + ;; + cmp.ne.or.andcm p6,p7=r14,r0 + ;; +(p7) ld4 r20=[in0],8 +(p7) ld4 r21=[r15],8 +(p6) br.spnt .generic + ;; + ld4 r22=[in0],8 + ld4 r23=[r15],8 + ;; + ld4 r24=[in0] + add r20=r20,r21 + add r22=r22,r23 + ;; + add r20=r20,r22 + ;; + add r20=r20,r24 + ;; + shr.u ret0=r20,16 // now need to add the carry + zxt2 r20=r20 + ;; + add r20=ret0,r20 + ;; + shr.u ret0=r20,16 // add carry again + zxt2 r20=r20 + ;; + add r20=ret0,r20 + ;; + shr.u ret0=r20,16 + zxt2 r20=r20 + ;; + add r20=ret0,r20 + mov r9=0xffff + ;; + andcm ret0=r9,r20 + .restore sp // reset frame state + br.ret.sptk.many b0 + ;; + +.generic: + .prologue + .save ar.pfs, r35 + alloc r35=ar.pfs,2,2,2,0 + .save rp, r34 + mov r34=b0 + .body + dep.z out1=in1,2,30 + mov out0=in0 + ;; + br.call.sptk.many b0=do_csum + ;; + andcm ret0=-1,ret0 + mov ar.pfs=r35 + mov b0=r34 + br.ret.sptk.many b0 +END(ip_fast_csum) + +GLOBAL_ENTRY(csum_ipv6_magic) + ld4 r20=[in0],4 + ld4 r21=[in1],4 + zxt4 in2=in2 + ;; + ld4 r22=[in0],4 + ld4 r23=[in1],4 + dep r15=in3,in2,32,16 + ;; + ld4 r24=[in0],4 + ld4 r25=[in1],4 + mux1 r15=r15,@rev + add r16=r20,r21 + add r17=r22,r23 + zxt4 in4=in4 + ;; + ld4 r26=[in0],4 + ld4 r27=[in1],4 + shr.u r15=r15,16 + add r18=r24,r25 + add r8=r16,r17 + ;; + add r19=r26,r27 + add r8=r8,r18 + ;; + add r8=r8,r19 + add r15=r15,in4 + ;; + add r8=r8,r15 + ;; + shr.u r10=r8,32 // now fold sum into short + zxt4 r11=r8 + ;; + add r8=r10,r11 + ;; + shr.u r10=r8,16 // yeah, keep it rolling + zxt2 r11=r8 + ;; + add r8=r10,r11 + ;; + shr.u r10=r8,16 // three times lucky + zxt2 r11=r8 + ;; + add r8=r10,r11 + mov r9=0xffff + ;; + andcm r8=r9,r8 + br.ret.sptk.many b0 +END(csum_ipv6_magic) |