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Length: 1566 (0x61e)
Types: TextFile
Names: »vaxbcopy.s«
└─⟦52210d11f⟧ Bits:30007239 EUUGD2: TeX 3 1992-12
└─⟦af5ba6c8e⟧ »unix3.0/DVIWARE.tar.Z«
└─⟦ca79c7339⟧
└─⟦this⟧ »DVIware/laser-setters/mctex/lib/vaxbcopy.s«
# # Copyright (c) 1987, 1989 University of Maryland # Department of Computer Science. All rights reserved. # Permission to copy for any purpose is hereby granted # so long as this copyright notice remains intact. # rcsid: .asciz "$Header: /usr/src/local/tex/local/mctex/lib/RCS/vaxbcopy.s,v 3.1 89/08/22 21:40:54 chris Exp $" # bcopy (from, to, count) char *from, *to; int count; # # Copy "count" bytes from "from" to "to". # Works even if the regions overlap. .align 2 .globl _bcopy _bcopy: .word 0x40 # r6 movl 4(ap),r1 # r1 = from movl 8(ap),r3 # r3 = to movl 12(ap),r6 # r6 = len cmpl r1,r3 bgtr 2f # moving forward, overlap irrelevant blss 3f # moving backward, overlap matters ret # not moving at all 1: subl2 r0,r6 # count -= 65535 (bytes moved this time) movc3 r0,(r1),(r3) # r1, r3 magically point to next 65K 2: movzwl $65535,r0 cmpl r6,r0 # <= 65535 bytes to move? jgtr 1b # brif not, move 65535 and try again movc3 r6,(r1),(r3) # move up to 65535 bytes ret 3: addl2 r6,r1 # start at end (from += len) addl2 r6,r3 # (to += len) movzwl $65535,r0 # r0 = 65535 jbr 5f # enter loop at bottom 4: subl2 r0,r6 # count -= 65535 (bytes to move now) subl2 r0,r1 # adjust from and to by -65535 subl2 r0,r3 movc3 r0,(r1),(r3) # move the bytes movzwl $65535,r0 # set r0 again subl2 r0,r1 # and adjust from and to subl2 r0,r3 # (since movc3 added 65535 to them) 5: cmpl r6,r0 # len <= 65535? jgtr 4b # no, do another 65535 subl2 r6,r1 # yes, just do the last few bytes subl2 r6,r3 movc3 r6,(r1),(r3) # swoop ret