| /* |
| * 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> |
| |
| /* |
| * Computes the checksum of a memory block at buff, length len, |
| * and adds in "sum" (32-bit). |
| * |
| * __csum_partial(r3=buff, r4=len, r5=sum) |
| */ |
| _GLOBAL(__csum_partial) |
| addic r0,r5,0 /* clear carry */ |
| |
| srdi. r6,r4,3 /* less than 8 bytes? */ |
| beq .Lcsum_tail_word |
| |
| /* |
| * If only halfword aligned, align to a double word. Since odd |
| * aligned addresses should be rare and they would require more |
| * work to calculate the correct checksum, we ignore that case |
| * and take the potential slowdown of unaligned loads. |
| */ |
| rldicl. r6,r3,64-1,64-2 /* r6 = (r3 & 0x3) >> 1 */ |
| beq .Lcsum_aligned |
| |
| li r7,4 |
| sub r6,r7,r6 |
| mtctr r6 |
| |
| 1: |
| lhz r6,0(r3) /* align to doubleword */ |
| subi r4,r4,2 |
| addi r3,r3,2 |
| adde r0,r0,r6 |
| bdnz 1b |
| |
| .Lcsum_aligned: |
| /* |
| * We unroll the loop such that each iteration is 64 bytes with an |
| * entry and exit limb of 64 bytes, meaning a minimum size of |
| * 128 bytes. |
| */ |
| srdi. r6,r4,7 |
| beq .Lcsum_tail_doublewords /* len < 128 */ |
| |
| srdi r6,r4,6 |
| subi r6,r6,1 |
| mtctr r6 |
| |
| stdu r1,-STACKFRAMESIZE(r1) |
| std r14,STK_REG(R14)(r1) |
| std r15,STK_REG(R15)(r1) |
| std r16,STK_REG(R16)(r1) |
| |
| ld r6,0(r3) |
| ld r9,8(r3) |
| |
| ld r10,16(r3) |
| ld r11,24(r3) |
| |
| /* |
| * On POWER6 and POWER7 back to back adde instructions take 2 cycles |
| * because of the XER dependency. This means the fastest this loop can |
| * go is 16 cycles per iteration. The scheduling of the loop below has |
| * been shown to hit this on both POWER6 and POWER7. |
| */ |
| .align 5 |
| 2: |
| adde r0,r0,r6 |
| ld r12,32(r3) |
| ld r14,40(r3) |
| |
| adde r0,r0,r9 |
| ld r15,48(r3) |
| ld r16,56(r3) |
| addi r3,r3,64 |
| |
| adde r0,r0,r10 |
| |
| adde r0,r0,r11 |
| |
| adde r0,r0,r12 |
| |
| adde r0,r0,r14 |
| |
| adde r0,r0,r15 |
| ld r6,0(r3) |
| ld r9,8(r3) |
| |
| adde r0,r0,r16 |
| ld r10,16(r3) |
| ld r11,24(r3) |
| bdnz 2b |
| |
| |
| adde r0,r0,r6 |
| ld r12,32(r3) |
| ld r14,40(r3) |
| |
| adde r0,r0,r9 |
| ld r15,48(r3) |
| ld r16,56(r3) |
| addi r3,r3,64 |
| |
| adde r0,r0,r10 |
| adde r0,r0,r11 |
| adde r0,r0,r12 |
| adde r0,r0,r14 |
| adde r0,r0,r15 |
| adde r0,r0,r16 |
| |
| ld r14,STK_REG(R14)(r1) |
| ld r15,STK_REG(R15)(r1) |
| ld r16,STK_REG(R16)(r1) |
| addi r1,r1,STACKFRAMESIZE |
| |
| andi. r4,r4,63 |
| |
| .Lcsum_tail_doublewords: /* Up to 127 bytes to go */ |
| srdi. r6,r4,3 |
| beq .Lcsum_tail_word |
| |
| mtctr r6 |
| 3: |
| ld r6,0(r3) |
| addi r3,r3,8 |
| adde r0,r0,r6 |
| bdnz 3b |
| |
| andi. r4,r4,7 |
| |
| .Lcsum_tail_word: /* Up to 7 bytes to go */ |
| srdi. r6,r4,2 |
| beq .Lcsum_tail_halfword |
| |
| lwz r6,0(r3) |
| addi r3,r3,4 |
| adde r0,r0,r6 |
| subi r4,r4,4 |
| |
| .Lcsum_tail_halfword: /* Up to 3 bytes to go */ |
| srdi. r6,r4,1 |
| beq .Lcsum_tail_byte |
| |
| lhz r6,0(r3) |
| addi r3,r3,2 |
| adde r0,r0,r6 |
| subi r4,r4,2 |
| |
| .Lcsum_tail_byte: /* Up to 1 byte to go */ |
| andi. r6,r4,1 |
| beq .Lcsum_finish |
| |
| lbz r6,0(r3) |
| sldi r9,r6,8 /* Pad the byte out to 16 bits */ |
| adde r0,r0,r9 |
| |
| .Lcsum_finish: |
| addze r0,r0 /* add in final carry */ |
| rldicl r4,r0,32,0 /* fold two 32 bit halves together */ |
| add r3,r4,r0 |
| srdi r3,r3,32 |
| blr |
| |
| |
| .macro srcnr |
| 100: |
| .section __ex_table,"a" |
| .align 3 |
| .llong 100b,.Lsrc_error_nr |
| .previous |
| .endm |
| |
| .macro source |
| 150: |
| .section __ex_table,"a" |
| .align 3 |
| .llong 150b,.Lsrc_error |
| .previous |
| .endm |
| |
| .macro dstnr |
| 200: |
| .section __ex_table,"a" |
| .align 3 |
| .llong 200b,.Ldest_error_nr |
| .previous |
| .endm |
| |
| .macro dest |
| 250: |
| .section __ex_table,"a" |
| .align 3 |
| .llong 250b,.Ldest_error |
| .previous |
| .endm |
| |
| /* |
| * 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. The caller must take any action |
| * required in this case (zeroing memory, recalculating partial checksum etc). |
| * |
| * 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 /* clear carry */ |
| |
| srdi. r6,r5,3 /* less than 8 bytes? */ |
| beq .Lcopy_tail_word |
| |
| /* |
| * If only halfword aligned, align to a double word. Since odd |
| * aligned addresses should be rare and they would require more |
| * work to calculate the correct checksum, we ignore that case |
| * and take the potential slowdown of unaligned loads. |
| * |
| * If the source and destination are relatively unaligned we only |
| * align the source. This keeps things simple. |
| */ |
| rldicl. r6,r3,64-1,64-2 /* r6 = (r3 & 0x3) >> 1 */ |
| beq .Lcopy_aligned |
| |
| li r9,4 |
| sub r6,r9,r6 |
| mtctr r6 |
| |
| 1: |
| srcnr; lhz r6,0(r3) /* align to doubleword */ |
| subi r5,r5,2 |
| addi r3,r3,2 |
| adde r0,r0,r6 |
| dstnr; sth r6,0(r4) |
| addi r4,r4,2 |
| bdnz 1b |
| |
| .Lcopy_aligned: |
| /* |
| * We unroll the loop such that each iteration is 64 bytes with an |
| * entry and exit limb of 64 bytes, meaning a minimum size of |
| * 128 bytes. |
| */ |
| srdi. r6,r5,7 |
| beq .Lcopy_tail_doublewords /* len < 128 */ |
| |
| srdi r6,r5,6 |
| subi r6,r6,1 |
| mtctr r6 |
| |
| stdu r1,-STACKFRAMESIZE(r1) |
| std r14,STK_REG(R14)(r1) |
| std r15,STK_REG(R15)(r1) |
| std r16,STK_REG(R16)(r1) |
| |
| source; ld r6,0(r3) |
| source; ld r9,8(r3) |
| |
| source; ld r10,16(r3) |
| source; ld r11,24(r3) |
| |
| /* |
| * On POWER6 and POWER7 back to back adde instructions take 2 cycles |
| * because of the XER dependency. This means the fastest this loop can |
| * go is 16 cycles per iteration. The scheduling of the loop below has |
| * been shown to hit this on both POWER6 and POWER7. |
| */ |
| .align 5 |
| 2: |
| adde r0,r0,r6 |
| source; ld r12,32(r3) |
| source; ld r14,40(r3) |
| |
| adde r0,r0,r9 |
| source; ld r15,48(r3) |
| source; ld r16,56(r3) |
| addi r3,r3,64 |
| |
| adde r0,r0,r10 |
| dest; std r6,0(r4) |
| dest; std r9,8(r4) |
| |
| adde r0,r0,r11 |
| dest; std r10,16(r4) |
| dest; std r11,24(r4) |
| |
| adde r0,r0,r12 |
| dest; std r12,32(r4) |
| dest; std r14,40(r4) |
| |
| adde r0,r0,r14 |
| dest; std r15,48(r4) |
| dest; std r16,56(r4) |
| addi r4,r4,64 |
| |
| adde r0,r0,r15 |
| source; ld r6,0(r3) |
| source; ld r9,8(r3) |
| |
| adde r0,r0,r16 |
| source; ld r10,16(r3) |
| source; ld r11,24(r3) |
| bdnz 2b |
| |
| |
| adde r0,r0,r6 |
| source; ld r12,32(r3) |
| source; ld r14,40(r3) |
| |
| adde r0,r0,r9 |
| source; ld r15,48(r3) |
| source; ld r16,56(r3) |
| addi r3,r3,64 |
| |
| adde r0,r0,r10 |
| dest; std r6,0(r4) |
| dest; std r9,8(r4) |
| |
| adde r0,r0,r11 |
| dest; std r10,16(r4) |
| dest; std r11,24(r4) |
| |
| adde r0,r0,r12 |
| dest; std r12,32(r4) |
| dest; std r14,40(r4) |
| |
| adde r0,r0,r14 |
| dest; std r15,48(r4) |
| dest; std r16,56(r4) |
| addi r4,r4,64 |
| |
| adde r0,r0,r15 |
| adde r0,r0,r16 |
| |
| ld r14,STK_REG(R14)(r1) |
| ld r15,STK_REG(R15)(r1) |
| ld r16,STK_REG(R16)(r1) |
| addi r1,r1,STACKFRAMESIZE |
| |
| andi. r5,r5,63 |
| |
| .Lcopy_tail_doublewords: /* Up to 127 bytes to go */ |
| srdi. r6,r5,3 |
| beq .Lcopy_tail_word |
| |
| mtctr r6 |
| 3: |
| srcnr; ld r6,0(r3) |
| addi r3,r3,8 |
| adde r0,r0,r6 |
| dstnr; std r6,0(r4) |
| addi r4,r4,8 |
| bdnz 3b |
| |
| andi. r5,r5,7 |
| |
| .Lcopy_tail_word: /* Up to 7 bytes to go */ |
| srdi. r6,r5,2 |
| beq .Lcopy_tail_halfword |
| |
| srcnr; lwz r6,0(r3) |
| addi r3,r3,4 |
| adde r0,r0,r6 |
| dstnr; stw r6,0(r4) |
| addi r4,r4,4 |
| subi r5,r5,4 |
| |
| .Lcopy_tail_halfword: /* Up to 3 bytes to go */ |
| srdi. r6,r5,1 |
| beq .Lcopy_tail_byte |
| |
| srcnr; lhz r6,0(r3) |
| addi r3,r3,2 |
| adde r0,r0,r6 |
| dstnr; sth r6,0(r4) |
| addi r4,r4,2 |
| subi r5,r5,2 |
| |
| .Lcopy_tail_byte: /* Up to 1 byte to go */ |
| andi. r6,r5,1 |
| beq .Lcopy_finish |
| |
| srcnr; lbz r6,0(r3) |
| sldi r9,r6,8 /* Pad the byte out to 16 bits */ |
| adde r0,r0,r9 |
| dstnr; stb r6,0(r4) |
| |
| .Lcopy_finish: |
| addze r0,r0 /* add in final carry */ |
| rldicl r4,r0,32,0 /* fold two 32 bit halves together */ |
| add r3,r4,r0 |
| srdi r3,r3,32 |
| blr |
| |
| .Lsrc_error: |
| ld r14,STK_REG(R14)(r1) |
| ld r15,STK_REG(R15)(r1) |
| ld r16,STK_REG(R16)(r1) |
| addi r1,r1,STACKFRAMESIZE |
| .Lsrc_error_nr: |
| cmpdi 0,r7,0 |
| beqlr |
| li r6,-EFAULT |
| stw r6,0(r7) |
| blr |
| |
| .Ldest_error: |
| ld r14,STK_REG(R14)(r1) |
| ld r15,STK_REG(R15)(r1) |
| ld r16,STK_REG(R16)(r1) |
| addi r1,r1,STACKFRAMESIZE |
| .Ldest_error_nr: |
| cmpdi 0,r8,0 |
| beqlr |
| li r6,-EFAULT |
| stw r6,0(r8) |
| blr |
