diff options
Diffstat (limited to 'arch/alpha/lib/ev6-copy_user.S')
| -rw-r--r-- | arch/alpha/lib/ev6-copy_user.S | 104 |
1 files changed, 45 insertions, 59 deletions
diff --git a/arch/alpha/lib/ev6-copy_user.S b/arch/alpha/lib/ev6-copy_user.S index be720b5..35e6710 100644 --- a/arch/alpha/lib/ev6-copy_user.S +++ b/arch/alpha/lib/ev6-copy_user.S @@ -12,21 +12,6 @@ * only _after_ a successful copy). There is also some rather minor * exception setup stuff.. * - * NOTE! This is not directly C-callable, because the calling semantics are - * different: - * - * Inputs: - * length in $0 - * destination address in $6 - * source address in $7 - * return address in $28 - * - * Outputs: - * bytes left to copy in $0 - * - * Clobbers: - * $1,$2,$3,$4,$5,$6,$7 - * * Much of the information about 21264 scheduling/coding comes from: * Compiler Writer's Guide for the Alpha 21264 * abbreviated as 'CWG' in other comments here @@ -60,10 +45,11 @@ # Pipeline info: Slotting & Comments __copy_user: .prologue 0 - subq $0, 32, $1 # .. E .. .. : Is this going to be a small copy? + andq $18, $18, $0 + subq $18, 32, $1 # .. E .. .. : Is this going to be a small copy? beq $0, $zerolength # U .. .. .. : U L U L - and $6,7,$3 # .. .. .. E : is leading dest misalignment + and $16,7,$3 # .. .. .. E : is leading dest misalignment ble $1, $onebyteloop # .. .. U .. : 1st branch : small amount of data beq $3, $destaligned # .. U .. .. : 2nd (one cycle fetcher stall) subq $3, 8, $3 # E .. .. .. : L U U L : trip counter @@ -73,17 +59,17 @@ __copy_user: * We know we have at least one trip through this loop */ $aligndest: - EXI( ldbu $1,0($7) ) # .. .. .. L : Keep loads separate from stores - addq $6,1,$6 # .. .. E .. : Section 3.8 in the CWG + EXI( ldbu $1,0($17) ) # .. .. .. L : Keep loads separate from stores + addq $16,1,$16 # .. .. E .. : Section 3.8 in the CWG addq $3,1,$3 # .. E .. .. : nop # E .. .. .. : U L U L /* - * the -1 is to compensate for the inc($6) done in a previous quadpack + * the -1 is to compensate for the inc($16) done in a previous quadpack * which allows us zero dependencies within either quadpack in the loop */ - EXO( stb $1,-1($6) ) # .. .. .. L : - addq $7,1,$7 # .. .. E .. : Section 3.8 in the CWG + EXO( stb $1,-1($16) ) # .. .. .. L : + addq $17,1,$17 # .. .. E .. : Section 3.8 in the CWG subq $0,1,$0 # .. E .. .. : bne $3, $aligndest # U .. .. .. : U L U L @@ -92,29 +78,29 @@ $aligndest: * If we arrived via branch, we have a minimum of 32 bytes */ $destaligned: - and $7,7,$1 # .. .. .. E : Check _current_ source alignment + and $17,7,$1 # .. .. .. E : Check _current_ source alignment bic $0,7,$4 # .. .. E .. : number bytes as a quadword loop - EXI( ldq_u $3,0($7) ) # .. L .. .. : Forward fetch for fallthrough code + EXI( ldq_u $3,0($17) ) # .. L .. .. : Forward fetch for fallthrough code beq $1,$quadaligned # U .. .. .. : U L U L /* - * In the worst case, we've just executed an ldq_u here from 0($7) + * In the worst case, we've just executed an ldq_u here from 0($17) * and we'll repeat it once if we take the branch */ /* Misaligned quadword loop - not unrolled. Leave it that way. */ $misquad: - EXI( ldq_u $2,8($7) ) # .. .. .. L : + EXI( ldq_u $2,8($17) ) # .. .. .. L : subq $4,8,$4 # .. .. E .. : - extql $3,$7,$3 # .. U .. .. : - extqh $2,$7,$1 # U .. .. .. : U U L L + extql $3,$17,$3 # .. U .. .. : + extqh $2,$17,$1 # U .. .. .. : U U L L bis $3,$1,$1 # .. .. .. E : - EXO( stq $1,0($6) ) # .. .. L .. : - addq $7,8,$7 # .. E .. .. : + EXO( stq $1,0($16) ) # .. .. L .. : + addq $17,8,$17 # .. E .. .. : subq $0,8,$0 # E .. .. .. : U L L U - addq $6,8,$6 # .. .. .. E : + addq $16,8,$16 # .. .. .. E : bis $2,$2,$3 # .. .. E .. : nop # .. E .. .. : bne $4,$misquad # U .. .. .. : U L U L @@ -125,8 +111,8 @@ $misquad: beq $0,$zerolength # U .. .. .. : U L U L /* We know we have at least one trip through the byte loop */ - EXI ( ldbu $2,0($7) ) # .. .. .. L : No loads in the same quad - addq $6,1,$6 # .. .. E .. : as the store (Section 3.8 in CWG) + EXI ( ldbu $2,0($17) ) # .. .. .. L : No loads in the same quad + addq $16,1,$16 # .. .. E .. : as the store (Section 3.8 in CWG) nop # .. E .. .. : br $31, $dirtyentry # L0 .. .. .. : L U U L /* Do the trailing byte loop load, then hop into the store part of the loop */ @@ -136,8 +122,8 @@ $misquad: * Based upon the usage context, it's worth the effort to unroll this loop * $0 - number of bytes to be moved * $4 - number of bytes to move as quadwords - * $6 is current destination address - * $7 is current source address + * $16 is current destination address + * $17 is current source address */ $quadaligned: subq $4, 32, $2 # .. .. .. E : do not unroll for small stuff @@ -155,29 +141,29 @@ $quadaligned: * instruction memory hint instruction). */ $unroll4: - EXI( ldq $1,0($7) ) # .. .. .. L - EXI( ldq $2,8($7) ) # .. .. L .. + EXI( ldq $1,0($17) ) # .. .. .. L + EXI( ldq $2,8($17) ) # .. .. L .. subq $4,32,$4 # .. E .. .. nop # E .. .. .. : U U L L - addq $7,16,$7 # .. .. .. E - EXO( stq $1,0($6) ) # .. .. L .. - EXO( stq $2,8($6) ) # .. L .. .. + addq $17,16,$17 # .. .. .. E + EXO( stq $1,0($16) ) # .. .. L .. + EXO( stq $2,8($16) ) # .. L .. .. subq $0,16,$0 # E .. .. .. : U L L U - addq $6,16,$6 # .. .. .. E - EXI( ldq $1,0($7) ) # .. .. L .. - EXI( ldq $2,8($7) ) # .. L .. .. + addq $16,16,$16 # .. .. .. E + EXI( ldq $1,0($17) ) # .. .. L .. + EXI( ldq $2,8($17) ) # .. L .. .. subq $4, 32, $3 # E .. .. .. : U U L L : is there enough for another trip? - EXO( stq $1,0($6) ) # .. .. .. L - EXO( stq $2,8($6) ) # .. .. L .. + EXO( stq $1,0($16) ) # .. .. .. L + EXO( stq $2,8($16) ) # .. .. L .. subq $0,16,$0 # .. E .. .. - addq $7,16,$7 # E .. .. .. : U L L U + addq $17,16,$17 # E .. .. .. : U L L U nop # .. .. .. E nop # .. .. E .. - addq $6,16,$6 # .. E .. .. + addq $16,16,$16 # .. E .. .. bgt $3,$unroll4 # U .. .. .. : U L U L nop @@ -186,14 +172,14 @@ $unroll4: beq $4, $noquads $onequad: - EXI( ldq $1,0($7) ) + EXI( ldq $1,0($17) ) subq $4,8,$4 - addq $7,8,$7 + addq $17,8,$17 nop - EXO( stq $1,0($6) ) + EXO( stq $1,0($16) ) subq $0,8,$0 - addq $6,8,$6 + addq $16,8,$16 bne $4,$onequad $noquads: @@ -207,23 +193,23 @@ $noquads: * There's no point in doing a lot of complex alignment calculations to try to * to quadword stuff for a small amount of data. * $0 - remaining number of bytes left to copy - * $6 - current dest addr - * $7 - current source addr + * $16 - current dest addr + * $17 - current source addr */ $onebyteloop: - EXI ( ldbu $2,0($7) ) # .. .. .. L : No loads in the same quad - addq $6,1,$6 # .. .. E .. : as the store (Section 3.8 in CWG) + EXI ( ldbu $2,0($17) ) # .. .. .. L : No loads in the same quad + addq $16,1,$16 # .. .. E .. : as the store (Section 3.8 in CWG) nop # .. E .. .. : nop # E .. .. .. : U L U L $dirtyentry: /* - * the -1 is to compensate for the inc($6) done in a previous quadpack + * the -1 is to compensate for the inc($16) done in a previous quadpack * which allows us zero dependencies within either quadpack in the loop */ - EXO ( stb $2,-1($6) ) # .. .. .. L : - addq $7,1,$7 # .. .. E .. : quadpack as the load + EXO ( stb $2,-1($16) ) # .. .. .. L : + addq $17,1,$17 # .. .. E .. : quadpack as the load subq $0,1,$0 # .. E .. .. : change count _after_ copy bgt $0,$onebyteloop # U .. .. .. : U L U L @@ -233,7 +219,7 @@ $exitout: # Destination for exception recovery(?) nop # .. .. .. E nop # .. .. E .. nop # .. E .. .. - ret $31,($28),1 # L0 .. .. .. : L U L U + ret $31,($26),1 # L0 .. .. .. : L U L U .end __copy_user EXPORT_SYMBOL(__copy_user) |
