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#++
#
# Copyright (c) 1993 by
# Digital Equipment Corporation, Maynard, MA
#
# This software is furnished under a license and may be used and copied
# only in accordance with the terms of such license and with the
# inclusion of the above copyright notice. This software or any other
# copies thereof may not be provided or otherwise made available to any
# other person. No title to and ownership of the software is hereby
# transferred.
#
# The information in this software is subject to change without notice
# and should not be construed as a commitment by Digital Equipment
# Corporation.
#
# Digital assumes no responsibility for the use or reliability of its
# software on equipment which is not supplied by Digital.
#
# Facility:
#
# GEM/OTS - GEM compiler system support library
#
# Abstract:
#
# OTS character string support, Alpha version
#
# Authors:
#
# Bill Noyce
#
#
# long ots_strcmp_eqls(char *str1, long strlen, char *str2);
# compares two strings of the same length.
# returns r0=1 if str1=str2, r0=0 otherwise.
# long ots_strcmp_eql(char *str1, long str1len, char *str2, long str2len);
# compares two strings of different lengths, without padding.
# returns r0=1 if str1=str2, r0=0 otherwise.
#
# Special conventions: No stack space, r16-r21 and r27-r28 ONLY,
# no linkage pointer required.
# (Warning: The auto-loader potentially takes some regs across
# the call if this is being used in a shared lib. environment.)
#
# Modification history:
#
# 005 27 Aug 1991 WBN Initial version, replacing BLISS -004
#
# 006 19 May 1992 KDG Changes for common VMS/OSF sources
#
# 007 22 Sep 1992 KDG Add case-sensitive name
#
# 008 26 Jan 1993 KDG Add underscore
#--
#include "ots_defs.hs"
# r16 --> A
# r17 = len
# r18 --> B
# returns r0=1 if equal, r0=0 if not equal
# destroys r16-r21, r27-r28
#.align octa
.globl _OtsStringCompareEqlSameLen .ent _OtsStringCompareEqlSameLen_OtsStringCompareEqlSameLen: .set noat .set noreorder .frame sp,0,r26 subq r17, 8, r19 # More than 8 bytes to compare?
beq r17, equal # Done if empty strings
join: ldq_u r20, (r16) # Get first QW containing part of A
addq r18, r17, r27 # Point to end of B
ldq_u r21, (r18) # Get first QW containing part of B
bgt r19, big # Skip if more than 8 bytes
ldq_u r27, -1(r27) # Get last QW containing part of B
addq r16, r17, r28 # Point to end of A
extql r20, r16, r20 # Get first part of A
ldq_u r28, -1(r28) # Get last QW containing part of A
extql r21, r18, r21 # Get first part of B
extqh r27, r18, r27 # Get last part of B
extqh r28, r16, r28 # Get last part of A
or r21, r27, r27 # Combine B
or r20, r28, r28 # Combine A
xor r28, r27, r0 # Are they different?
extqh r0, r19, r0 # Discard differences after length
nop
cmpeq r0, 0, r0 # Return 1 or 0 as xor=0 or not
ret r31, (r26)
equal: mov 1, r0 # Return true
ret r31, (r26)
# r16 --> A
# r17 = A_len
# r18 --> B
# r19 = B_len
# returns r0=1 if equal, r0=0 if not equal
# destroys r16-r21, r27-r28
#
nop #.align octa
nop
.globl _OtsStringCompareEql .aent _OtsStringCompareEql_OtsStringCompareEql: .frame sp,0,r26 cmpeq r17, r19, r0 # Are lengths equal?
beq r17, done # If one is zero, no compares needed
subq r17, 8, r19 # More than 8 bytes to compare?
blbs r0, join # Only compare if lengths equal
done: ret r31, (r26) # Return result of length comparison
#.odd
big: and r16, 7, r0 # A alignment, or amount not compared
subq r18, r0, r18 # Back up B pointer that much
and r18, 7, r17 # Is B now aligned?
addq r19, r0, r19 # (Len-8+align) is amount left to do
ldq_u r27, 8(r18) # Get next QW of B
subq r19, 16, r19 # More than 2 QW's left?
bne r17, unalign # Skip if B alignment doesn't match
xor r20, r21, r0 # Compare first (partial) QW
ldq_u r28, 8(r16) # Get next QW of A
mskqh r0, r16, r0 # Discard junk preceding strings
ble r19, bottom # Skip if two quadwords or less to go
# stall
loop: ldq_u r20, 16(r16) # Get yet another QW of A
bne r0, not_eq # Done if difference in prior compare
xor r28, r27, r0 # Compare prior QW's
ldq r21, 16(r18) # Get yet another QW of B
subq r19, 16, r19 # Decrement length
bne r0, not_eq # Done if difference in this compare
ldq r27, 24(r18) # Get next QW of B
addq r18, 16, r18 # Increment pointer
ldq_u r28, 24(r16) # Get next QW of A
addq r16, 16, r16 # Increment pointer
xor r20, r21, r0 # Compare QW's loaded at top of loop
bgt r19, loop # Repeat until two or less QWs left
bottom: addq r19, 8, r19 # More than 1 QW left?
bne r0, not_eq # Done if difference in prior compare
xor r28, r27, r0 # Compare QW's just loaded
ble r19, last # Skip if this is last compare
ldq_u r28, 16(r16) # Get last QW of A
bne r0, not_eq # Done if difference in this compare
ldq r27, 16(r18) # Get last QW of B
#2 stalls
xor r28, r27, r0 # Compare last QW's
last: extqh r0, r19, r0 # Discard diffs after length
nop
cmpeq r0, 0, r0 # Return 1 or 0 as xor=0 or not
ret r31, (r26) #.align quad
unalign: extql r21, r18, r21 # Get first part of B
extqh r27, r18, r0 # Get second part of B
#stall
or r0, r21, r21 # Combine pieces of B
xor r20, r21, r0 # Compare with A
mskqh r0, r16, r0 # Trim junk preceding strings
blt r19, bott_u # Skip if fewer than 16 bytes left
loop_u: ldq_u r21, 16(r18) # Get more B
subq r19, 16, r19 # Decrement length
extql r27, r18, r17 # Get piece of B from prior QW
bne r0, not_eq # Done if r1.ne.r2
ldq_u r27, 24(r18) # Get still more B
addq r18, 16, r18 # Increment B pointer
ldq_u r28, 8(r16) # Get more A
extqh r21, r18, r0 # Get piece of B from first QW in loop
ldq_u r20, 16(r16) # Get still more A
extql r21, r18, r21 # Get second piece of B from there
or r17, r0, r17 # Combine pieces for first B
xor r28, r17, r0 # Compare with first A
extqh r27, r18, r17 # Start building second B
bne r0, not_eq # Done if r28.ne.r17
addq r16, 16, r16 # Increment A pointer
or r17, r21, r21 # Combine pieces for second B
xor r20, r21, r0 # Compare with second A
bge r19, loop_u # Repeat if at least 16 more bytes
bott_u: and r19, 8, r17 # At least 8 more bytes?
bne r0, not_eq # Done if r1.ne.r2
and r19, 7, r19 # How many odd bytes?
beq r17, last_u # Skip if not a whole QW
extql r27, r18, r17 # Get a piece of B
ldq_u r27, 16(r18) # Load another QW of B
addq r18, 8, r18 # Increment B pointer
ldq_u r28, 8(r16) # Load another QW of A
addq r16, 8, r16 # Increment A pointer
extqh r27, r18, r0 # Get a piece of new B QW
#stall
or r17, r0, r17 # Combine pieces
xor r28, r17, r0 # Compare with A
nop bne r0, not_eq # Done if r28.ne.r17
last_u: addq r18, r19, r17 # Point to end of B
beq r19, eql_u # Return true if no more bytes
ldq_u r28, 8(r16) # Get last QW of A
ldq_u r20, 7(r17) # Get QW containing end of B
extql r27, r18, r27 # Get piece of prior B QW
#stall
extqh r20, r18, r0 # Get a piece of last B QW
#stall
or r27, r0, r27 # Combine
xor r28, r27, r0 # Compare with A
mskql r0, r19, r0 # Discard diffs after strings
nop
eql_u: cmpeq r0, 0, r0 # Return 1 or 0 as xor=0 or not
ret r31, (r26)
not_eq: clr r0 # Return false
ret r31, (r26)
.set at .set reorder .end _OtsStringCompareEqlSameLen
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