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-rw-r--r--arch/sparc/lib/memscan.S133
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+/* $Id: memscan.S,v 1.4 1996/09/08 02:01:20 davem Exp $
+ * memscan.S: Optimized memscan for the Sparc.
+ *
+ * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
+ */
+
+/* In essence, this is just a fancy strlen. */
+
+#define LO_MAGIC 0x01010101
+#define HI_MAGIC 0x80808080
+
+ .text
+ .align 4
+ .globl __memscan_zero, __memscan_generic
+ .globl memscan
+__memscan_zero:
+ /* %o0 = addr, %o1 = size */
+ cmp %o1, 0
+ bne,a 1f
+ andcc %o0, 3, %g0
+
+ retl
+ nop
+
+1:
+ be mzero_scan_word
+ sethi %hi(HI_MAGIC), %g2
+
+ ldsb [%o0], %g3
+mzero_still_not_word_aligned:
+ cmp %g3, 0
+ bne 1f
+ add %o0, 1, %o0
+
+ retl
+ sub %o0, 1, %o0
+
+1:
+ subcc %o1, 1, %o1
+ bne,a 1f
+ andcc %o0, 3, %g0
+
+ retl
+ nop
+
+1:
+ bne,a mzero_still_not_word_aligned
+ ldsb [%o0], %g3
+
+ sethi %hi(HI_MAGIC), %g2
+mzero_scan_word:
+ or %g2, %lo(HI_MAGIC), %o3
+ sethi %hi(LO_MAGIC), %g3
+ or %g3, %lo(LO_MAGIC), %o2
+mzero_next_word:
+ ld [%o0], %g2
+mzero_next_word_preloaded:
+ sub %g2, %o2, %g2
+mzero_next_word_preloaded_next:
+ andcc %g2, %o3, %g0
+ bne mzero_byte_zero
+ add %o0, 4, %o0
+
+mzero_check_out_of_fuel:
+ subcc %o1, 4, %o1
+ bg,a 1f
+ ld [%o0], %g2
+
+ retl
+ nop
+
+1:
+ b mzero_next_word_preloaded_next
+ sub %g2, %o2, %g2
+
+ /* Check every byte. */
+mzero_byte_zero:
+ ldsb [%o0 - 4], %g2
+ cmp %g2, 0
+ bne mzero_byte_one
+ sub %o0, 4, %g3
+
+ retl
+ mov %g3, %o0
+
+mzero_byte_one:
+ ldsb [%o0 - 3], %g2
+ cmp %g2, 0
+ bne,a mzero_byte_two_and_three
+ ldsb [%o0 - 2], %g2
+
+ retl
+ sub %o0, 3, %o0
+
+mzero_byte_two_and_three:
+ cmp %g2, 0
+ bne,a 1f
+ ldsb [%o0 - 1], %g2
+
+ retl
+ sub %o0, 2, %o0
+
+1:
+ cmp %g2, 0
+ bne,a mzero_next_word_preloaded
+ ld [%o0], %g2
+
+ retl
+ sub %o0, 1, %o0
+
+mzero_found_it:
+ retl
+ sub %o0, 2, %o0
+
+memscan:
+__memscan_generic:
+ /* %o0 = addr, %o1 = c, %o2 = size */
+ cmp %o2, 0
+ bne,a 0f
+ ldub [%o0], %g2
+
+ b,a 2f
+1:
+ ldub [%o0], %g2
+0:
+ cmp %g2, %o1
+ be 2f
+ addcc %o2, -1, %o2
+ bne 1b
+ add %o0, 1, %o0
+2:
+ retl
+ nop
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