diff options
Diffstat (limited to 'private/crt32/string/ppc/memcmpp.s')
| -rw-r--r-- | private/crt32/string/ppc/memcmpp.s | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/private/crt32/string/ppc/memcmpp.s b/private/crt32/string/ppc/memcmpp.s new file mode 100644 index 000000000..ce1b003ff --- /dev/null +++ b/private/crt32/string/ppc/memcmpp.s @@ -0,0 +1,71 @@ +// TITLE("memcmp") +//++ +// +// Copyright (c) 1994 IBM Corporation +// +// Module Name: +// +// memcmp.s +// +// Routine Description: +// +// This function lexically determines two blocks of memory and +// returns an integer indicating order. +// +// Author: +// +// Jeff Simon (jhs) 02-Aug-1994 +// +// Environment: +// +// User or Kernel mode. +// +// Revision History: +// +// Includes + +#include <kxppc.h> + +// +// int memcmp ( +// void * src1, +// void * src2, +// int +// ) +// +// Arguments: +// +// SRC1 (r.3) - A pointer to the first block of memory +// +// SRC2 (r.4) - A pointer to the second block of memory +// +// LNGTH (r.5) - Max number of comparison in bytes +// +// Return Value: +// +// < 0 if SRC1 < SRC2 +// = 0 if SRC1 = SRC2 for LNGTH bytes, or if LNGTH == 0 +// > 0 if SRC1 > SRC2 +// +// + + LEAF_ENTRY(memcmp) + + cmpwi r.5,0 // we'll do the first iteration + mtctr r.5 // by hand, iff length > 0 + beq zip // branch if nothing to check + lbz r.6,0(r.4) // read first byte + lbz r.5,0(r.3) // of both strings + b comp + +next: lbzu r.6,1(r.4) // get next byte (src2) + lbzu r.5,1(r.3) // get next byte (src1) +comp: cmpw r.5,r.6 // bytes equal? + bdnzt eq,next // branch equal AND length not exhausted + + subf r.3,r.6,r.5 // r7 ?= r8 + blr + +zip: li r.3,0 // return null when length == 0 + + LEAF_EXIT(memcmp) |