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+ new, complete implementation of move procedure (including support for
overlapping regions)
This commit is contained in:
Jonas Maebe
parent
6874cceff4
commit
b7970bf7a4
@ -24,80 +24,148 @@
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{$define FPC_SYSTEM_HAS_MOVE}
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procedure Move(var source;var dest;count:longint);
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begin
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{ register usage:
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r3 source
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r4 dest
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r5 count
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r13 ptr to end of source
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r14 ptr to end of dest
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r15 counter 1
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r16 counter 2
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r17 addr increment
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r18 ptr to current source block
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r19 ptr to current dest block
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r20-24 buffer
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f1-4 buffer
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ctr Loop counter
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notes:
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Move uses FPRs for increased bandwidth
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}
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asm
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{ do some param checking, initialization }
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cmplwi cr2,r3,0
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cmplwi cr3,r4,0
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cmplw cr4,r3,r4
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add r13,r3,r5
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add r14,r4,r5
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bt cr2,.MoveEnd //end if source=nil
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bt cr3,.MoveEnd //end if dest=nil
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bt cr4,.MoveEnd //end if source=dest
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{ see if source and dest overlap }
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cmplw cr2,r13,r4
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cmplw cr3,r4,r3
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srawi. r15,r5,$5 //r15 := count div 32
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andi r16,r5,$1F //r16 := count mod 32
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crand cr3,cr2,cr3
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mtctr r15 //Load loop counter
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bgt cr3,.MoveRL //dest overlaps source on right
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li r17,$8 //Offset 8 bytes per doubleword copy
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sub r18,r17,r3 //calculate the starting source
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sub r19,r17,r4 // and dest ptrs
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beq .MoveByByte //If count<32 skip 32 byte block copy
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srawi. r15,r16,$2 //r15 := r16 div 4
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andi r16,r15,$3 //r16 := r15 mod 4
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cmpwi cr2,r16,0 //r16 = 0 ?
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crand cr3,cr2,cr0 //r15 = 0 AND r16 = 0 ?
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.MoveBlockLoop: //32 Byte block copy (fully optimized)
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lfdux f1,r18,r17
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lfdux f2,r18,r17
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lfdux f3,r18,r17
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lfdux f4,r18,r17
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stfdux f1,r19,r17
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stfdux f2,r19,r17
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stfdux f3,r19,r17
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stfdux f4,r19,r17
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bdnz .MoveBlockLoop
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procedure Move(var sou{}rce;var dest;count:longint);assembler;
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asm
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{ count <= 0 ? }
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cmpwi cr0,r5,0
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{ check if we have to do the move backwards because of overlap }
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sub r30,r4,r3
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{ carry := boolean(dest-source < count) = boolean(overlap) }
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subc r30,r30,r5
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{ count < 11 ? (to decide whether we will move dwords or bytes }
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cmpwi cr1,r5,11
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{ if overlap, then r30 := -1 else r30 := 0 }
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subfe r30,r30,r30
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{ count < 39 ? (32 + max. alignment (7) }
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cmpwi cr7,r5,39
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{ if count <= 0, stop }
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ble cr0,LMoveDone
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{ if overlap, then r29 := count else r29 := 0 }
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and r29,r5,r30
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{ if overlap, then point source and dest to the end }
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add r3,r3,r29
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add r4,r4,r29
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{ if overlap, then r29 := 0, else r29 := -1 }
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not r29,r30
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{ if overlap, then r30 := -2, else r30 := 0 }
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slwi r30,r30,1
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{ if overlap, then r30 := -1, else r30 := 1 }
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addi r30,r30,1
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{ if overlap, then source/dest += -1, otherwise they stay }
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{ After the next instruction, r3/r4 + r30 = next position }
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{ to load/store from/to }
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add r3,r3,r29
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add r4,r4,r29
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bt cr3,MoveEnd //Nothing left to do...
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mtspr 1,r16 //XER := r16
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beq .MoveBytes //There are fewer than 4 bytes left
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mtctr r15 //load counter
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andi r15,r15,$3 //r15 := r15 mod 4
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srawi r17,$1 //Offset := Offset div 2
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.MoveWordLoop: //4 byte copy
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lwzux r20,r18,r17
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stwux r20,r19,r17
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bdnz .WordCopyLoop
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{ if count < 11, copy everything byte by byte }
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blt cr1,LMoveBytes
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bt cr2,MoveEnd //Nothing left to do...
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.MoveBytes: //Copy remaining stragglers
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lswx r20,r0,r18
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stswx r20,r0,r19
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.MoveEnd:
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End;
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End;
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{ otherwise, guarantee 4 byte alignment for dest for starters }
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LMove4ByteAlignLoop:
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lbzux r29,r3,r30
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stbux r29,r4,r30
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{ is dest now 4 aligned? }
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andi. r29,r4,3
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subi r5,r5,1
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{ while not aligned, continue }
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bne cr0,LMove4ByteAlignLoop
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{ check for 8 byte alignment }
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andi. r29,r4,7
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{ we are going to copy one byte again (the one at the newly }
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{ aligned address), so increase count again }
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addi r5,r5,1
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{ count div 4 for number of dwords to copy }
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srwi r29,r5,2
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{ if 11 <= count < 39, copy using dwords }
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blt cr7,LMoveDWords
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beq cr0,L8BytesAligned
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{ count >= 39 -> align to 8 byte boundary and then use the FPU }
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{ since we're already at 4 byte alignment, use dword store }
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lwzux r29,r3,r30
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stwux r29,r4,r30
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L8BytesAligned:
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{ count div 32 ( >= 1, since count was >=39 }
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srwi r29,r5,5
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{ remainder }
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andi. r5,r5,31
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{ to decide if we will do some dword stores afterwards or not }
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cmpwi cr1,r5,11
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mtctr r29
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{ r29 := count div 4, will be moved to ctr when copying dwords }
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srwi r29,r5,2
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{ adjust the update count: it will now be 8 or -8 depending on overlap }
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slwi r30,r30,3
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{ adjust source and dest pointers: because of the above loop, dest is now }
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{ aligned to 8 bytes. So if we substract r30 we will still have an 8 bytes }
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{ aligned address) }
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sub r3,r3,r30
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sub r4,r4,r30
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LMove32ByteLoop:
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lfdux f31,r3,r30
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lfdux f30,r3,r30
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lfdux f29,r3,r30
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lfdux f28,r3,r30
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stfdux f31,r4,r30
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stfdux f30,r4,r30
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stfdux f29,r4,r30
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stfdux f28,r4,r30
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bdnz LMove32ByteLoop
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{ cr0*4+eq is true if "count and 31" = 0 }
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beq cr0,LMoveDone
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{ make r30 again -1 or 1, but first adjust source/dest pointers }
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add r3,r3,r30
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add r4,r4,r30
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srawi r30,r30,3
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sub r3,r3,r30
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sub r4,r4,r30
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{ cr1 contains whether count <= 11 }
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ble cr1,LMoveBytes
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add r3,r3,r30
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add r4,r4,r30
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LMoveDWords:
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mtctr r29
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andi. r5,r5,3
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{ r30 * 4 }
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slwi r30,r30,2
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sub r3,r3,r30
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sub r4,r4,r30
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LMoveDWordsLoop:
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lwzux r29,r3,r30
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stwux r29,r4,r30
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bdnz LMoveDWordsLoop
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beq cr0,LMoveDone
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{ make r30 again -1 or 1 }
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add r3,r3,r30
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add r4,r4,r30
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srawi r30,r30,2
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sub r3,r3,r30
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sub r4,r4,r30
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LMoveBytes:
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mtctr r5
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LMoveBytesLoop:
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lbzux r29,r3,r30
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stbux r29,r4,r30
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bdnz LMoveBytesLoop
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LMoveDone:
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end ['R3','R4','R5','R29','R30','F28','F29','F30','F31','CTR','CR0','CR1','CR7'];
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{$define FPC_SYSTEM_HAS_FILLCHAR}
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@ -380,7 +448,11 @@ end ['r3','r4','r5','r29','r30','cr0','ctr'];
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{
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$Log$
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Revision 1.2 2001-02-11 17:59:46 jonas
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Revision 1.3 2001-03-02 13:24:10 jonas
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+ new, complete implementation of move procedure (including support for
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overlapping regions)
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Revision 1.2 2001/02/11 17:59:46 jonas
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* implemented several more procedures
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Revision 1.1 2000/07/27 07:32:12 jonas
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