|
|
// TITLE("LPC Move Message Support")//++//// Copyright (c) 1990 Microsoft Corporation// Copyright (c) 1992 Digital Equipment Corporation//// Module Name://// lpcmove.s//// Abstract://// This module implements functions to support the efficient movement of// LPC Message blocks.//// Author://// David N. Cutler (davec) 11-Apr-1990//// Environment://// Kernel mode only.//// Revision History://// Thomas Van Baak (tvb) 19-May-1992//// Adapted for Alpha AXP.////--
#include "ksalpha.h"
SBTTL("Move Message")//++//// VOID// LpcpMoveMessage (// OUT PPORT_MESSAGE DstMsg// IN PPORT_MESSAGE SrcMsg// IN PUCHAR SrcMsgData// IN ULONG MsgType OPTIONAL,// IN PCLIENT_ID ClientId OPTIONAL// )//// Routine Description://// This function moves an LPC message block and optionally sets the message// type and client id to the specified values.//// Arguments://// DstMsg (a0) - Supplies a pointer to the destination message.//// SrcMsg (a1) - Supplies a pointer to the source message.//// SrcMsgData (a2) - Supplies a pointer to the source message data to// copy to destination.//// MsgType (a3) - If non-zero, then store in type field of the destination// message.//// ClientId (a4) - If non-NULL, then points to a ClientId to copy to// the destination message.//// N.B. The messages are assumed to be quadword aligned.//// Return Value://// None.////--
LEAF_ENTRY(LpcpMoveMessage)
ldq t0, PmLength(a1) // load first quadword of source
//// The message length is in the low word of the first quadword.//
addq t0, 3, t1 // round length to bic t1, 3, t0 // nearest 4-byte multiple
//// The message type is in the low half of the high longword. If a message// type was specified, use it instead of the message type in the source// message.//
sll a3, 32, t2 // shift message type into position zap t0, 0x30, t3 // clear message type field or t3, t2, t1 // merge into new field cmovne a3, t1, t0 // if a3!=0 use new message field stq t0, PmLength(a0) // store first quadword of destination
//// The client id is the third and fourth items. If a client id was// specified, use it instead of the client id in the source message.//
lda t3, PmClientId(a1) // get address of source client id cmovne a4, a4, t3 // if a4!=0, use client id address in a4
//// Move the process and thread ids into place. Note that for axp32, (t3) isn't// necessarily quadword aligned.//
LDP t2, CidUniqueProcess(t3)// load low part of client id LDP t1, CidUniqueThread(t3) // load high part of client id STP t2, PmProcess(a0) // store third longword of destination STP t1, PmThread(a0) // store fourth longword of destination #if defined(_AXP64_)
//// Copy MessageId and ClientViewSize. //
ldl t2,PmMessageId(a1) stl t2,PmMessageId(a0) ldq t2,PmClientViewSize(a1) stq t2,PmClientViewSize(a0)
#else
//// PmClientViewSize is adjacent to PmMessageId, both can be moved at once// with a single quadword move.//
ldq t2,PmMessageId(a1) // get next quadword of source stq t2,PmMessageId(a0) // set next quadword of destination
#endif
and t0, 0xfff8, t3 // isolate quadword move count beq t3,20f // if eq, no quadwords to move and a2, 7, t1 // check if source is quadword aligned bne t1, UnalignedSource // if ne, not quadword aligned
//// Source and destination are both quadword aligned, use ldq/stq. Use of// the constant "PortMessageLength-8" is used in lieu of an additional// instruction to increment a0 by that amount before entering the copy// loop.//
5: ldq t1, 0(a2) // get source qword ADDP a0, 8, a0 // advance destination address ADDP a2, 8, a2 // advance source address subq t3, 8, t3 // decrement number of bytes remaining stq t1, PortMessageLength-8(a0) // store destination qword bne t3, 5b // if ne, more quadwords to store br zero, 20f // move remaining longword
//// We know that the destination is quadword aligned, but the source is// not. Use ldq_u to load the low and high parts of the source quadword,// merge them with EXTQx and store them as one quadword.//// By reusing the result of the second ldq_u as the source for the// next quadword's EXTQL we end up doing one ldq_u/stq for each quadword,// regardless of the source's alignment.//
UnalignedSource: // ldq_u t1, 0(a2) // prime t1 with low half of qword10: extql t1, a2, t2 // t2 is aligned low part ADDP a0, 8, a0 // advance destination address subq t3, 8, t3 // reduce number of bytes remaining ldq_u t1, 7(a2) // t1 has high part extqh t1, a2, t4 // t4 is aligned high part ADDP a2, 8, a2 // advance source address bis t2, t4, t5 // merge high and low parts stq t5, PortMessageLength-8(a0) // store result bne t3, 10b // if ne, more quadwords to move
//// Move remaining longword (if any)//
20: and t0, 4, t0 // check if longword to move beq t0, 50f // if eq, no longword to move ldl t1, 0(a2) // move last longword to move stl t1, PortMessageLength(a0) //50: ret zero, (ra) // return
.end LpcpMoveMessage
|
