mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-18 17:54:13 +08:00
1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
114 lines
2.6 KiB
ArmAsm
114 lines
2.6 KiB
ArmAsm
/*
|
|
* arch/alpha/lib/clear_user.S
|
|
* Contributed by Richard Henderson <rth@tamu.edu>
|
|
*
|
|
* Zero user space, handling exceptions as we go.
|
|
*
|
|
* We have to make sure that $0 is always up-to-date and contains the
|
|
* right "bytes left to zero" value (and that it is updated 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
|
|
* exception pointer in $7
|
|
* return address in $28 (exceptions expect it there)
|
|
*
|
|
* Outputs:
|
|
* bytes left to copy in $0
|
|
*
|
|
* Clobbers:
|
|
* $1,$2,$3,$4,$5,$6
|
|
*/
|
|
|
|
/* Allow an exception for an insn; exit if we get one. */
|
|
#define EX(x,y...) \
|
|
99: x,##y; \
|
|
.section __ex_table,"a"; \
|
|
.long 99b - .; \
|
|
lda $31, $exception-99b($31); \
|
|
.previous
|
|
|
|
.set noat
|
|
.set noreorder
|
|
.align 4
|
|
|
|
.globl __do_clear_user
|
|
.ent __do_clear_user
|
|
.frame $30, 0, $28
|
|
.prologue 0
|
|
|
|
$loop:
|
|
and $1, 3, $4 # e0 :
|
|
beq $4, 1f # .. e1 :
|
|
|
|
0: EX( stq_u $31, 0($6) ) # e0 : zero one word
|
|
subq $0, 8, $0 # .. e1 :
|
|
subq $4, 1, $4 # e0 :
|
|
addq $6, 8, $6 # .. e1 :
|
|
bne $4, 0b # e1 :
|
|
unop # :
|
|
|
|
1: bic $1, 3, $1 # e0 :
|
|
beq $1, $tail # .. e1 :
|
|
|
|
2: EX( stq_u $31, 0($6) ) # e0 : zero four words
|
|
subq $0, 8, $0 # .. e1 :
|
|
EX( stq_u $31, 8($6) ) # e0 :
|
|
subq $0, 8, $0 # .. e1 :
|
|
EX( stq_u $31, 16($6) ) # e0 :
|
|
subq $0, 8, $0 # .. e1 :
|
|
EX( stq_u $31, 24($6) ) # e0 :
|
|
subq $0, 8, $0 # .. e1 :
|
|
subq $1, 4, $1 # e0 :
|
|
addq $6, 32, $6 # .. e1 :
|
|
bne $1, 2b # e1 :
|
|
|
|
$tail:
|
|
bne $2, 1f # e1 : is there a tail to do?
|
|
ret $31, ($28), 1 # .. e1 :
|
|
|
|
1: EX( ldq_u $5, 0($6) ) # e0 :
|
|
clr $0 # .. e1 :
|
|
nop # e1 :
|
|
mskqh $5, $0, $5 # e0 :
|
|
EX( stq_u $5, 0($6) ) # e0 :
|
|
ret $31, ($28), 1 # .. e1 :
|
|
|
|
__do_clear_user:
|
|
and $6, 7, $4 # e0 : find dest misalignment
|
|
beq $0, $zerolength # .. e1 :
|
|
addq $0, $4, $1 # e0 : bias counter
|
|
and $1, 7, $2 # e1 : number of bytes in tail
|
|
srl $1, 3, $1 # e0 :
|
|
beq $4, $loop # .. e1 :
|
|
|
|
EX( ldq_u $5, 0($6) ) # e0 : load dst word to mask back in
|
|
beq $1, $oneword # .. e1 : sub-word store?
|
|
|
|
mskql $5, $6, $5 # e0 : take care of misaligned head
|
|
addq $6, 8, $6 # .. e1 :
|
|
EX( stq_u $5, -8($6) ) # e0 :
|
|
addq $0, $4, $0 # .. e1 : bytes left -= 8 - misalignment
|
|
subq $1, 1, $1 # e0 :
|
|
subq $0, 8, $0 # .. e1 :
|
|
br $loop # e1 :
|
|
unop # :
|
|
|
|
$oneword:
|
|
mskql $5, $6, $4 # e0 :
|
|
mskqh $5, $2, $5 # e0 :
|
|
or $5, $4, $5 # e1 :
|
|
EX( stq_u $5, 0($6) ) # e0 :
|
|
clr $0 # .. e1 :
|
|
|
|
$zerolength:
|
|
$exception:
|
|
ret $31, ($28), 1 # .. e1 :
|
|
|
|
.end __do_clear_user
|