diff options
Diffstat (limited to 'libc/string/metag/strchr.S')
| -rw-r--r-- | libc/string/metag/strchr.S | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/libc/string/metag/strchr.S b/libc/string/metag/strchr.S new file mode 100644 index 000000000..6b0f2ea43 --- /dev/null +++ b/libc/string/metag/strchr.S @@ -0,0 +1,167 @@ +! Copyright (C) 2013 Imagination Technologies Ltd. + +! Licensed under LGPL v2.1 or later, see the file COPYING.LIB in this tarball. + + +#include <features.h> + + .text + .global _strchr + .type _strchr, function +! D1Ar1 src +! D0Ar2 c +_strchr: + AND D0Ar2,D0Ar2,#0xff ! Drop all but 8 bits of c + MOV D1Ar5, D1Ar1 ! Copy src to D1Ar5 + AND D1Ar5, D1Ar5, #7 ! Check 64 bit alignment + CMP D1Ar5, #0 + BZ $Laligned64bit ! Jump to 64 bit aligned strchr +$Lalign64bit: + GETB D0Re0, [D1Ar1++] ! Get the next character + ADD D1Ar5, D1Ar5, #1 ! Increment alignment counter + CMP D0Re0, D0Ar2 ! Is the char c + BZ $Lcharatprevious ! If so exit returning position + CMP D0Re0, #0 ! End of string? + BZ $Lnotfound ! If so exit + CMP D1Ar5, #8 ! Are we aligned 64bit yet? + BNZ $Lalign64bit ! If not keep aligning +$Laligned64bit: ! src is 64bit aligned + MOV D0Ar4, D0Ar2 ! put c into D0Ar4 + LSL D0Ar4, D0Ar4, #8 ! Shift it up + ADD D0Ar4, D0Ar4, D0Ar2 ! another c + LSL D0Ar4, D0Ar4, #8 ! shift + ADD D0Ar4, D0Ar4, D0Ar2 ! another c + LSL D0Ar4, D0Ar4, #8 ! shift + ADD D0Ar4, D0Ar4, D0Ar2 ! 4 copies of c +$Lcheck8bytes: + GETL D0Re0, D1Re0, [D1Ar1++] ! grab 16 bytes + MOV A0.3, D0Re0 ! save for later use + ! first word + ! check for \0 + MOV D0Ar2, D0Re0 ! D0Ar2 is a scratch now + ADDT D0Re0, D0Re0, #HI(0xfefefeff) ! Do 4 1-byte compares + ADD D0Re0, D0Re0, #LO(0xfefefeff) + XOR D0Ar2, D0Ar2, #-1 + AND D0Re0, D0Re0, D0Ar2 + ANDMT D0Re0, D0Re0, #HI(0x80808080) + ANDMB D0Re0, D0Re0, #LO(0x80808080) + CMP D0Re0, #0 + BNZ $Lnullinword1 ! found \0 (or c if c==\0) + + ! Check for c + MOV D0Re0, A0.3 ! restore the first word + XOR D0Re0, D0Re0, D0Ar4 + MOV D0Ar2, D0Re0 ! DO 4 1-byte compares + ADDT D0Re0, D0Re0, #HI(0xfefefeff) + ADD D0Re0, D0Re0, #LO(0xfefefeff) + XOR D0Ar2, D0Ar2, #-1 + AND D0Re0, D0Re0, D0Ar2 + ANDMT D0Re0, D0Re0, #HI(0x80808080) + ANDMB D0Re0, D0Re0, #LO(0x80808080) + CMP D0Re0, #0 + BNZ $Lcharinword1 ! found c + + ! second word + ! check for \0 + MOV A0.3, D1Re0 ! save for later use + MOV D1Ar3, D1Re0 + ADDT D1Re0, D1Re0, #HI(0xfefefeff) ! Do 4 1-byte compares + ADD D1Re0, D1Re0, #LO(0xfefefeff) + XOR D1Ar3, D1Ar3, #-1 + AND D1Re0, D1Re0, D1Ar3 + ANDMT D1Re0, D1Re0, #HI(0x80808080) + ANDMB D1Re0, D1Re0, #LO(0x80808080) + CMP D1Re0, #0 + BNZ $Lnullinword2 ! Found \0 (or c if c==\0) + + MOV D0.4, A0.3 ! restore the second word + XOR D1Re0, D0.4, D0Ar4 ! test c + + MOV D1Ar3, D1Re0 + ADDT D1Re0, D1Re0, #HI(0xfefefeff) ! Do 4 1-byte compares + ADD D1Re0, D1Re0, #LO(0xfefefeff) + XOR D1Ar3, D1Ar3, #-1 + AND D1Re0, D1Re0, D1Ar3 + ANDMT D1Re0, D1Re0, #HI(0x80808080) + ANDMB D1Re0, D1Re0, #LO(0x80808080) + CMP D1Re0, #0 + BNZ $Lcharinword2 ! found c + + B $Lcheck8bytes ! Keep checking + +$Lnullinword1: ! found \0 somewhere, check for c too + SUB D1Ar1, D1Ar1, #4 +$Lnullinword2: + SUB D1Ar1, D1Ar1, #4 + AND D0Ar2, D0Ar4, #0xff ! restore c + MOV D0Re0, A0.3 ! restore the word + MOV D0.4, D0Re0 ! for shifting later + AND D0Re0, D0Re0, #0xff ! take first byte of word + CMP D0Re0, D0Ar2 + BZ $Lcharatcurrent ! found c + CMP D0Re0, #0! + BZ $Lnotfound ! found \0 + + ADD D1Ar1, D1Ar1, #1 + LSR D0.4, D0.4, #8 + MOV D0Re0, D0.4 + AND D0Re0, D0Re0, #0xff ! take second byte of word + CMP D0Re0, D0Ar2 + BZ $Lcharatcurrent ! found c + CMP D0Re0, #0 + BZ $Lnotfound ! found \0 + + ADD D1Ar1, D1Ar1, #1 + LSR D0.4, D0.4, #8 + MOV D0Re0, D0.4 + AND D0Re0, D0Re0, #0xff ! take third byte of word + CMP D0Re0, D0Ar2 + BZ $Lcharatcurrent ! found c + CMP D0Re0, #0 + BZ $Lnotfound ! found \0 + + ADD D1Ar1, D1Ar1, #1 ! move to 4th byte + CMP D0Ar2, #0 ! If c was \0 + BZ $Lcharatcurrent ! c has been found! + +$Lnotfound: + MOV D0Re0, #0 ! End of string c not found + B $Lend + +$Lcharinword1: ! found c in first word + MOV D1Re0, D0Re0 + SUB D1Ar1, D1Ar1, #4 +$Lcharinword2: ! found c in second word + SUB D1Ar1, D1Ar1, #4 + + AND D0Re0, D1Re0, #0xff ! First byte + CMP D0Re0, #0 ! Test c (zero indicates c due + ! to the 4 1-byte compare code) + BNE $Lcharatcurrent + ADD D1Ar1, D1Ar1, #1 + + LSR D1Re0, D1Re0, #8 + AND D0Re0, D1Re0, #0xff ! Second byte + CMP D0Re0, #0 ! Test c (indicated by zero) + BNE $Lcharatcurrent + ADD D1Ar1, D1Ar1, #1 + + LSR D1Re0, D1Re0, #8 + AND D0Re0, D1Re0, #0xff ! Third byte + CMP D0Re0, #0 ! Test c (indicated by zero) + BNE $Lcharatcurrent + ADD D1Ar1, D1Ar1, #1 ! Must be the fourth byte + B $Lcharatcurrent + +$Lcharatprevious: + SUB D1Ar1, D1Ar1, #1 ! Fix-up pointer +$Lcharatcurrent: + MOV D0Re0, D1Ar1 ! Return the string pointer +$Lend: + MOV PC, D1RtP + .size _strchr,.-_strchr + +libc_hidden_def(strchr) +#ifdef __UCLIBC_SUSV3_LEGACY__ +strong_alias(strchr,index) +#endif |