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-rw-r--r--arch/alpha/lib/strlen_user.S91
1 files changed, 0 insertions, 91 deletions
diff --git a/arch/alpha/lib/strlen_user.S b/arch/alpha/lib/strlen_user.S
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-/*
- * arch/alpha/lib/strlen_user.S
- *
- * Return the length of the string including the NUL terminator
- * (strlen+1) or zero if an error occurred.
- *
- * In places where it is critical to limit the processing time,
- * and the data is not trusted, strnlen_user() should be used.
- * It will return a value greater than its second argument if
- * that limit would be exceeded. This implementation is allowed
- * to access memory beyond the limit, but will not cross a page
- * boundary when doing so.
- */
-
-#include <asm/regdef.h>
-
-
-/* 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 v0, $exception-99b(zero); \
- .previous
-
-
- .set noreorder
- .set noat
- .text
-
- .globl __strlen_user
- .ent __strlen_user
- .frame sp, 0, ra
-
- .align 3
-__strlen_user:
- ldah a1, 32767(zero) # do not use plain strlen_user() for strings
- # that might be almost 2 GB long; you should
- # be using strnlen_user() instead
-
- .globl __strnlen_user
-
- .align 3
-__strnlen_user:
- .prologue 0
-
- EX( ldq_u t0, 0(a0) ) # load first quadword (a0 may be misaligned)
- lda t1, -1(zero)
- insqh t1, a0, t1
- andnot a0, 7, v0
- or t1, t0, t0
- subq a0, 1, a0 # get our +1 for the return
- cmpbge zero, t0, t1 # t1 <- bitmask: bit i == 1 <==> i-th byte == 0
- subq a1, 7, t2
- subq a0, v0, t0
- bne t1, $found
-
- addq t2, t0, t2
- addq a1, 1, a1
-
- .align 3
-$loop: ble t2, $limit
- EX( ldq t0, 8(v0) )
- subq t2, 8, t2
- addq v0, 8, v0 # addr += 8
- cmpbge zero, t0, t1
- beq t1, $loop
-
-$found: negq t1, t2 # clear all but least set bit
- and t1, t2, t1
-
- and t1, 0xf0, t2 # binary search for that set bit
- and t1, 0xcc, t3
- and t1, 0xaa, t4
- cmovne t2, 4, t2
- cmovne t3, 2, t3
- cmovne t4, 1, t4
- addq t2, t3, t2
- addq v0, t4, v0
- addq v0, t2, v0
- nop # dual issue next two on ev4 and ev5
- subq v0, a0, v0
-$exception:
- ret
-
- .align 3 # currently redundant
-$limit:
- subq a1, t2, v0
- ret
-
- .end __strlen_user