1 ! Copyright (C) 2008-2012 Imagination Technologies Ltd. 2 3 .text 4 .global _memset 5 .type _memset,function 6 ! D1Ar1 dst 7 ! D0Ar2 c 8 ! D1Ar3 cnt 9 ! D0Re0 dst 10 _memset: 11 AND D0Ar2,D0Ar2,#0xFF ! Ensure a byte input value 12 MULW D0Ar2,D0Ar2,#0x0101 ! Duplicate byte value into 0-15 13 ANDS D0Ar4,D1Ar1,#7 ! Extract bottom LSBs of dst 14 LSL D0Re0,D0Ar2,#16 ! Duplicate byte value into 16-31 15 ADD A0.2,D0Ar2,D0Re0 ! Duplicate byte value into 4 (A0.2) 16 MOV D0Re0,D1Ar1 ! Return dst 17 BZ $LLongStub ! if start address is aligned 18 ! start address is not aligned on an 8 byte boundary, so we 19 ! need the number of bytes up to the next 8 byte address 20 ! boundary, or the length of the string if less than 8, in D1Ar5 21 MOV D0Ar2,#8 ! Need 8 - N in D1Ar5 ... 22 SUB D1Ar5,D0Ar2,D0Ar4 ! ... subtract N 23 CMP D1Ar3,D1Ar5 24 MOVMI D1Ar5,D1Ar3 25 B $LByteStub ! dst is mis-aligned, do $LByteStub 26 27 ! 28 ! Preamble to LongLoop which generates 4*8 bytes per interation (5 cycles) 29 ! 30 $LLongStub: 31 LSRS D0Ar2,D1Ar3,#5 32 AND D1Ar3,D1Ar3,#0x1F 33 MOV A1.2,A0.2 34 BEQ $LLongishStub 35 SUB TXRPT,D0Ar2,#1 36 CMP D1Ar3,#0 37 $LLongLoop: 38 SETL [D1Ar1++],A0.2,A1.2 39 SETL [D1Ar1++],A0.2,A1.2 40 SETL [D1Ar1++],A0.2,A1.2 41 SETL [D1Ar1++],A0.2,A1.2 42 BR $LLongLoop 43 BZ $Lexit 44 ! 45 ! Preamble to LongishLoop which generates 1*8 bytes per interation (2 cycles) 46 ! 47 $LLongishStub: 48 LSRS D0Ar2,D1Ar3,#3 49 AND D1Ar3,D1Ar3,#0x7 50 MOV D1Ar5,D1Ar3 51 BEQ $LByteStub 52 SUB TXRPT,D0Ar2,#1 53 CMP D1Ar3,#0 54 $LLongishLoop: 55 SETL [D1Ar1++],A0.2,A1.2 56 BR $LLongishLoop 57 BZ $Lexit 58 ! 59 ! This does a byte structured burst of up to 7 bytes 60 ! 61 ! D1Ar1 should point to the location required 62 ! D1Ar3 should be the remaining total byte count 63 ! D1Ar5 should be burst size (<= D1Ar3) 64 ! 65 $LByteStub: 66 SUBS D1Ar3,D1Ar3,D1Ar5 ! Reduce count 67 ADD D1Ar1,D1Ar1,D1Ar5 ! Advance pointer to end of area 68 MULW D1Ar5,D1Ar5,#4 ! Scale to (1*4), (2*4), (3*4) 69 SUB D1Ar5,D1Ar5,#(8*4) ! Rebase to -(7*4), -(6*4), -(5*4), ... 70 MOV A1.2,D1Ar5 71 SUB PC,CPC1,A1.2 ! Jump into table below 72 SETB [D1Ar1+#(-7)],A0.2 73 SETB [D1Ar1+#(-6)],A0.2 74 SETB [D1Ar1+#(-5)],A0.2 75 SETB [D1Ar1+#(-4)],A0.2 76 SETB [D1Ar1+#(-3)],A0.2 77 SETB [D1Ar1+#(-2)],A0.2 78 SETB [D1Ar1+#(-1)],A0.2 79 ! 80 ! Return if all data has been output, otherwise do $LLongStub 81 ! 82 BNZ $LLongStub 83 $Lexit: 84 MOV PC,D1RtP 85 .size _memset,.-_memset 86 87
