| /* Copyright (C) 2000-2018 Free Software Foundation, Inc. |
| Contributed by Richard Henderson (rth@tamu.edu) |
| EV6 optimized by Rick Gorton <rick.gorton@alpha-processor.com>. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library. If not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <sysdep.h> |
| |
| .arch ev6 |
| .set noat |
| .set noreorder |
| |
| ENTRY(memset) |
| #ifdef PROF |
| ldgp gp, 0(pv) |
| lda AT, _mcount |
| jsr AT, (AT), _mcount |
| .prologue 1 |
| #else |
| .prologue 0 |
| #endif |
| |
| /* |
| * Serious stalling happens. The only way to mitigate this is to |
| * undertake a major re-write to interleave the constant materialization |
| * with other parts of the fall-through code. This is important, even |
| * though it makes maintenance tougher. |
| * Do this later. |
| */ |
| and $17, 255, $1 # E : 00000000000000ch |
| insbl $17, 1, $2 # U : 000000000000ch00 |
| mov $16, $0 # E : return value |
| ble $18, $end # U : zero length requested? |
| |
| addq $18, $16, $6 # E : max address to write to |
| or $1, $2, $17 # E : 000000000000chch |
| insbl $1, 2, $3 # U : 0000000000ch0000 |
| insbl $1, 3, $4 # U : 00000000ch000000 |
| |
| or $3, $4, $3 # E : 00000000chch0000 |
| inswl $17, 4, $5 # U : 0000chch00000000 |
| xor $16, $6, $1 # E : will complete write be within one quadword? |
| inswl $17, 6, $2 # U : chch000000000000 |
| |
| or $17, $3, $17 # E : 00000000chchchch |
| or $2, $5, $2 # E : chchchch00000000 |
| bic $1, 7, $1 # E : fit within a single quadword? |
| and $16, 7, $3 # E : Target addr misalignment |
| |
| or $17, $2, $17 # E : chchchchchchchch |
| beq $1, $within_quad # U : |
| nop # E : |
| beq $3, $aligned # U : target is 0mod8 |
| |
| /* |
| * Target address is misaligned, and won't fit within a quadword. |
| */ |
| ldq_u $4, 0($16) # L : Fetch first partial |
| mov $16, $5 # E : Save the address |
| insql $17, $16, $2 # U : Insert new bytes |
| subq $3, 8, $3 # E : Invert (for addressing uses) |
| |
| addq $18, $3, $18 # E : $18 is new count ($3 is negative) |
| mskql $4, $16, $4 # U : clear relevant parts of the quad |
| subq $16, $3, $16 # E : $16 is new aligned destination |
| or $2, $4, $1 # E : Final bytes |
| |
| nop |
| stq_u $1,0($5) # L : Store result |
| nop |
| nop |
| |
| .align 4 |
| $aligned: |
| /* |
| * We are now guaranteed to be quad aligned, with at least |
| * one partial quad to write. |
| */ |
| |
| sra $18, 3, $3 # U : Number of remaining quads to write |
| and $18, 7, $18 # E : Number of trailing bytes to write |
| mov $16, $5 # E : Save dest address |
| beq $3, $no_quad # U : tail stuff only |
| |
| /* |
| * It's worth the effort to unroll this and use wh64 if possible. |
| * At this point, entry values are: |
| * $16 Current destination address |
| * $5 A copy of $16 |
| * $6 The max quadword address to write to |
| * $18 Number trailer bytes |
| * $3 Number quads to write |
| */ |
| |
| and $16, 0x3f, $2 # E : Forward work (only useful for unrolled loop) |
| subq $3, 16, $4 # E : Only try to unroll if > 128 bytes |
| subq $2, 0x40, $1 # E : bias counter (aligning stuff 0mod64) |
| blt $4, $loop # U : |
| |
| /* |
| * We know we've got at least 16 quads, minimum of one trip |
| * through unrolled loop. Do a quad at a time to get us 0mod64 |
| * aligned. |
| */ |
| |
| nop # E : |
| nop # E : |
| nop # E : |
| beq $1, $bigalign # U : |
| |
| $alignmod64: |
| stq $17, 0($5) # L : |
| subq $3, 1, $3 # E : For consistency later |
| addq $1, 8, $1 # E : Increment towards zero for alignment |
| addq $5, 8, $4 # E : Initial wh64 address (filler instruction) |
| |
| nop |
| nop |
| addq $5, 8, $5 # E : Inc address |
| blt $1, $alignmod64 # U : |
| |
| $bigalign: |
| /* |
| * $3 - number quads left to go |
| * $5 - target address (aligned 0mod64) |
| * $17 - mask of stuff to store |
| * Scratch registers available: $7, $2, $4, $1 |
| * We know that we'll be taking a minimum of one trip through. |
| * CWG Section 3.7.6: do not expect a sustained store rate of > 1/cycle |
| * Assumes the wh64 needs to be for 2 trips through the loop in the future. |
| * The wh64 is issued on for the starting destination address for trip +2 |
| * through the loop, and if there are less than two trips left, the target |
| * address will be for the current trip. |
| */ |
| |
| $do_wh64: |
| wh64 ($4) # L1 : memory subsystem write hint |
| subq $3, 24, $2 # E : For determining future wh64 addresses |
| stq $17, 0($5) # L : |
| nop # E : |
| |
| addq $5, 128, $4 # E : speculative target of next wh64 |
| stq $17, 8($5) # L : |
| stq $17, 16($5) # L : |
| addq $5, 64, $7 # E : Fallback address for wh64 (== next trip addr) |
| |
| stq $17, 24($5) # L : |
| stq $17, 32($5) # L : |
| cmovlt $2, $7, $4 # E : Latency 2, extra mapping cycle |
| nop |
| |
| stq $17, 40($5) # L : |
| stq $17, 48($5) # L : |
| subq $3, 16, $2 # E : Repeat the loop at least once more? |
| nop |
| |
| stq $17, 56($5) # L : |
| addq $5, 64, $5 # E : |
| subq $3, 8, $3 # E : |
| bge $2, $do_wh64 # U : |
| |
| nop |
| nop |
| nop |
| beq $3, $no_quad # U : Might have finished already |
| |
| .align 4 |
| /* |
| * Simple loop for trailing quadwords, or for small amounts |
| * of data (where we can't use an unrolled loop and wh64) |
| */ |
| $loop: |
| stq $17, 0($5) # L : |
| subq $3, 1, $3 # E : Decrement number quads left |
| addq $5, 8, $5 # E : Inc address |
| bne $3, $loop # U : more? |
| |
| $no_quad: |
| /* |
| * Write 0..7 trailing bytes. |
| */ |
| nop # E : |
| beq $18, $end # U : All done? |
| ldq $7, 0($5) # L : |
| mskqh $7, $6, $2 # U : Mask final quad |
| |
| insqh $17, $6, $4 # U : New bits |
| or $2, $4, $1 # E : Put it all together |
| stq $1, 0($5) # L : And back to memory |
| ret $31,($26),1 # L0 : |
| |
| $within_quad: |
| ldq_u $1, 0($16) # L : |
| insql $17, $16, $2 # U : New bits |
| mskql $1, $16, $4 # U : Clear old |
| or $2, $4, $2 # E : New result |
| |
| mskql $2, $6, $4 # U : |
| mskqh $1, $6, $2 # U : |
| or $2, $4, $1 # E : |
| stq_u $1, 0($16) # L : |
| |
| $end: |
| nop |
| nop |
| nop |
| ret $31,($26),1 # L0 : |
| |
| END(memset) |
| libc_hidden_builtin_def (memset) |