| /* |
| * This file contains assembly-language implementations |
| * of IP-style 1's complement checksum routines. |
| * |
| * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| * |
| * Severely hacked about by Paul Mackerras (paulus@cs.anu.edu.au). |
| */ |
| |
| #include <linux/sys.h> |
| #include <asm/processor.h> |
| #include <asm/errno.h> |
| #include <asm/ppc_asm.h> |
| |
| /* |
| * ip_fast_csum(r3=buf, r4=len) -- Optimized for IP header |
| * len is in words and is always >= 5. |
| * |
| * In practice len == 5, but this is not guaranteed. So this code does not |
| * attempt to use doubleword instructions. |
| */ |
| _GLOBAL(ip_fast_csum) |
| lwz r0,0(r3) |
| lwzu r5,4(r3) |
| addic. r4,r4,-2 |
| addc r0,r0,r5 |
| mtctr r4 |
| blelr- |
| 1: lwzu r4,4(r3) |
| adde r0,r0,r4 |
| bdnz 1b |
| addze r0,r0 /* add in final carry */ |
| rldicl r4,r0,32,0 /* fold two 32-bit halves together */ |
| add r0,r0,r4 |
| srdi r0,r0,32 |
| rlwinm r3,r0,16,0,31 /* fold two halves together */ |
| add r3,r0,r3 |
| not r3,r3 |
| srwi r3,r3,16 |
| blr |
| |
| /* |
| * Compute checksum of TCP or UDP pseudo-header: |
| * csum_tcpudp_magic(r3=saddr, r4=daddr, r5=len, r6=proto, r7=sum) |
| * No real gain trying to do this specially for 64 bit, but |
| * the 32 bit addition may spill into the upper bits of |
| * the doubleword so we still must fold it down from 64. |
| */ |
| _GLOBAL(csum_tcpudp_magic) |
| rlwimi r5,r6,16,0,15 /* put proto in upper half of len */ |
| addc r0,r3,r4 /* add 4 32-bit words together */ |
| adde r0,r0,r5 |
| adde r0,r0,r7 |
| rldicl r4,r0,32,0 /* fold 64 bit value */ |
| add r0,r4,r0 |
| srdi r0,r0,32 |
| rlwinm r3,r0,16,0,31 /* fold two halves together */ |
| add r3,r0,r3 |
| not r3,r3 |
| srwi r3,r3,16 |
| blr |
| |
| /* |
| * Computes the checksum of a memory block at buff, length len, |
| * and adds in "sum" (32-bit). |
| * |
| * This code assumes at least halfword alignment, though the length |
| * can be any number of bytes. The sum is accumulated in r5. |
| * |
| * csum_partial(r3=buff, r4=len, r5=sum) |
| */ |
| _GLOBAL(csum_partial) |
| subi r3,r3,8 /* we'll offset by 8 for the loads */ |
| srdi. r6,r4,3 /* divide by 8 for doubleword count */ |
| addic r5,r5,0 /* clear carry */ |
| beq 3f /* if we're doing < 8 bytes */ |
| andi. r0,r3,2 /* aligned on a word boundary already? */ |
| beq+ 1f |
| lhz r6,8(r3) /* do 2 bytes to get aligned */ |
| addi r3,r3,2 |
| subi r4,r4,2 |
| addc r5,r5,r6 |
| srdi. r6,r4,3 /* recompute number of doublewords */ |
| beq 3f /* any left? */ |
| 1: mtctr r6 |
| 2: ldu r6,8(r3) /* main sum loop */ |
| adde r5,r5,r6 |
| bdnz 2b |
| andi. r4,r4,7 /* compute bytes left to sum after doublewords */ |
| 3: cmpwi 0,r4,4 /* is at least a full word left? */ |
| blt 4f |
| lwz r6,8(r3) /* sum this word */ |
| addi r3,r3,4 |
| subi r4,r4,4 |
| adde r5,r5,r6 |
| 4: cmpwi 0,r4,2 /* is at least a halfword left? */ |
| blt+ 5f |
| lhz r6,8(r3) /* sum this halfword */ |
| addi r3,r3,2 |
| subi r4,r4,2 |
| adde r5,r5,r6 |
| 5: cmpwi 0,r4,1 /* is at least a byte left? */ |
| bne+ 6f |
| lbz r6,8(r3) /* sum this byte */ |
| slwi r6,r6,8 /* this byte is assumed to be the upper byte of a halfword */ |
| adde r5,r5,r6 |
| 6: addze r5,r5 /* add in final carry */ |
| rldicl r4,r5,32,0 /* fold two 32-bit halves together */ |
| add r3,r4,r5 |
| srdi r3,r3,32 |
| blr |
| |
| /* |
| * Computes the checksum of a memory block at src, length len, |
| * and adds in "sum" (32-bit), while copying the block to dst. |
| * If an access exception occurs on src or dst, it stores -EFAULT |
| * to *src_err or *dst_err respectively, and (for an error on |
| * src) zeroes the rest of dst. |
| * |
| * This code needs to be reworked to take advantage of 64 bit sum+copy. |
| * However, due to tokenring halfword alignment problems this will be very |
| * tricky. For now we'll leave it until we instrument it somehow. |
| * |
| * csum_partial_copy_generic(r3=src, r4=dst, r5=len, r6=sum, r7=src_err, r8=dst_err) |
| */ |
| _GLOBAL(csum_partial_copy_generic) |
| addic r0,r6,0 |
| subi r3,r3,4 |
| subi r4,r4,4 |
| srwi. r6,r5,2 |
| beq 3f /* if we're doing < 4 bytes */ |
| andi. r9,r4,2 /* Align dst to longword boundary */ |
| beq+ 1f |
| 81: lhz r6,4(r3) /* do 2 bytes to get aligned */ |
| addi r3,r3,2 |
| subi r5,r5,2 |
| 91: sth r6,4(r4) |
| addi r4,r4,2 |
| addc r0,r0,r6 |
| srwi. r6,r5,2 /* # words to do */ |
| beq 3f |
| 1: mtctr r6 |
| 82: lwzu r6,4(r3) /* the bdnz has zero overhead, so it should */ |
| 92: stwu r6,4(r4) /* be unnecessary to unroll this loop */ |
| adde r0,r0,r6 |
| bdnz 82b |
| andi. r5,r5,3 |
| 3: cmpwi 0,r5,2 |
| blt+ 4f |
| 83: lhz r6,4(r3) |
| addi r3,r3,2 |
| subi r5,r5,2 |
| 93: sth r6,4(r4) |
| addi r4,r4,2 |
| adde r0,r0,r6 |
| 4: cmpwi 0,r5,1 |
| bne+ 5f |
| 84: lbz r6,4(r3) |
| 94: stb r6,4(r4) |
| slwi r6,r6,8 /* Upper byte of word */ |
| adde r0,r0,r6 |
| 5: addze r3,r0 /* add in final carry (unlikely with 64-bit regs) */ |
| rldicl r4,r3,32,0 /* fold 64 bit value */ |
| add r3,r4,r3 |
| srdi r3,r3,32 |
| blr |
| |
| /* These shouldn't go in the fixup section, since that would |
| cause the ex_table addresses to get out of order. */ |
| |
| .globl src_error_1 |
| src_error_1: |
| li r6,0 |
| subi r5,r5,2 |
| 95: sth r6,4(r4) |
| addi r4,r4,2 |
| srwi. r6,r5,2 |
| beq 3f |
| mtctr r6 |
| .globl src_error_2 |
| src_error_2: |
| li r6,0 |
| 96: stwu r6,4(r4) |
| bdnz 96b |
| 3: andi. r5,r5,3 |
| beq src_error |
| .globl src_error_3 |
| src_error_3: |
| li r6,0 |
| mtctr r5 |
| addi r4,r4,3 |
| 97: stbu r6,1(r4) |
| bdnz 97b |
| .globl src_error |
| src_error: |
| cmpdi 0,r7,0 |
| beq 1f |
| li r6,-EFAULT |
| stw r6,0(r7) |
| 1: addze r3,r0 |
| blr |
| |
| .globl dst_error |
| dst_error: |
| cmpdi 0,r8,0 |
| beq 1f |
| li r6,-EFAULT |
| stw r6,0(r8) |
| 1: addze r3,r0 |
| blr |
| |
| .section __ex_table,"a" |
| .align 3 |
| .llong 81b,src_error_1 |
| .llong 91b,dst_error |
| .llong 82b,src_error_2 |
| .llong 92b,dst_error |
| .llong 83b,src_error_3 |
| .llong 93b,dst_error |
| .llong 84b,src_error_3 |
| .llong 94b,dst_error |
| .llong 95b,dst_error |
| .llong 96b,dst_error |
| .llong 97b,dst_error |
