// Copyright (c) 1997-2009 Nokia Corporation and/or its subsidiary(-ies).
// All rights reserved.
// This component and the accompanying materials are made available
// under the terms of the License "Eclipse Public License v1.0"
// which accompanies this distribution, and is available
// at the URL "http://www.eclipse.org/legal/epl-v10.html".
//
// Initial Contributors:
// Nokia Corporation - initial contribution.
//
// Contributors:
//
// Description:
// e32\klib\arm\ckdes8.cia
// 
//

#include <e32cia.h>
#include <arm.h>
#include <kernel/kernel.h>

#ifdef __DES8_MACHINE_CODED__

GLREF_C void KUDesInfoPanicBadDesType();
GLREF_C void KUDesSetLengthPanicBadDesType();
GLREF_C void KUDesSetLengthPanicOverflow();
GLREF_C void Des8PanicBadDesType();

/**
Gets information about the specified descriptor.

If the current thread is a user thread, i.e. if the mode in spsr_svc is 'User',
then the descriptor is read using user mode privileges.

@param aSrc The descriptor for which information is to be fetched.
@param aLength On return, set to the length of the descriptor.
@param aMaxLength On return, set to the maximum length of the descriptor,
                  or 1 if the descriptor is not writable.

@return Address of first byte in descriptor.

@panic KERN-EXEC 33, if aSrc is not a valid descriptor type.

@pre  Do not call from User thread if in a critical section.
@pre  Interrupts must be enabled.
@pre  Kernel must be unlocked.
@pre  No fast mutex can be held.
@pre  Call in a thread context.
@pre  Can be used in a device driver.
*/
EXPORT_C __NAKED__ const TUint8* Kern::KUDesInfo(const TDesC8& /*aSrc*/, TInt& /*aLength*/, TInt& /*aMaxLength*/)
//
// Get information about a user descriptor
//
	{
	ASM_CHECK_PRECONDITIONS(MASK_NO_CRITICAL_IF_USER|MASK_INTERRUPTS_ENABLED|MASK_KERNEL_UNLOCKED|MASK_NOT_ISR|MASK_NOT_IDFC|MASK_NO_FAST_MUTEX);
	ASM_ASSERT_DATA_PAGING_SAFE		// todo: should this be ASM_ASSERT_PAGING_SAFE?

	asm("mrs ip, spsr ");
	asm("tst ip, #0x0f ");			// test for user or supervisor
	USER_MEMORY_GUARD_OFF(eq,r12,r12);
	asm("ldreqt r3, [r0], #4 ");	// if user r3=type/len
	USER_MEMORY_GUARD_ON(eq,r12,r12);
	asm("bne 1f ");					// branch if supervisor
	asm("bic ip, r3, #0xf0000000 ");	// ip=length
	asm("str ip, [r1] ");			// store length
	asm("mvn ip, #0 ");				// ip=max length=-1 if not writeable
	asm("cmp r3, #0x50000000 ");
	asm("bcs  " CSM_Z24KUDesInfoPanicBadDesTypev);
	asm("eor r3, r3, r3, lsr #1 ");
	asm("msr cpsr_flg, r3 ");
	USER_MEMORY_GUARD_OFF(,r1,r1);
	asm("ldrcst ip, [r0], #4 ");	// if writeable ip=max length and r0+=4
	asm("mov r1, r0 ");				// NB can't use ldrlet r0, [r0] - see ARM ARM
	asm("ldrlet r0, [r1] ");		// if pointer, r0=pointer field
	USER_MEMORY_GUARD_ON(,r1,r1);

	asm("2: ");
	asm("str ip, [r2] ");			// store max length
	asm("addeq r0, r0, #4 ");		// if BufCPtr, step r0 past TBufC length
	__JUMP(,lr);

	asm("1: ");
	asm("ldr r3, [r0], #4 ");		// r3=type/len
	asm("bic ip, r3, #0xf0000000 ");	// ip=length
	asm("str ip, [r1] ");			// store length
	asm("mvn ip, #0 ");				// ip=max length=-1 if not writeable
	asm("cmp r3, #0x50000000 ");
	asm("bcs  " CSM_Z24KUDesInfoPanicBadDesTypev);
	asm("eor r3, r3, r3, lsr #1 ");
	asm("msr cpsr_flg, r3 ");
	asm("ldrcs ip, [r0], #4 ");		// if writeable ip=max length and r0+=4
	asm("ldrle r0, [r0] ");			// if pointer, r0=pointer field
	asm("b 2b ");
	}


/**
Sets the length of the specified descriptor.

If the current thread is a user thread, i.e. if the mode in spsr_svc is 'User',
then the length is written using user mode privileges.

@param aDes The descriptor.
@param aLength The new descriptor length.

@panic KERN-EXEC 34, if aDes is not a modifiable descriptor type.
@panic KERN-EXEC 35, if aLength is longer that the maximum length of aDes.

@pre  Do not call from User thread if in a critical section.
@pre  Interrupts must be enabled.
@pre  Kernel must be unlocked.
@pre  No fast mutex can be held.
@pre  Call in a thread context.
@pre  Can be used in a device driver.

@post The length of aDes is equal to aLength.
@post If aDes is a TPtr type then its maximum length is equal its new length.
*/
EXPORT_C __NAKED__ void Kern::KUDesSetLength(TDes8& /*aDes*/, TInt /*aLength*/)
//
// Set the length of a user descriptor, checking the length is O.K.
//
	{
	ASM_CHECK_PRECONDITIONS(MASK_NO_CRITICAL_IF_USER|MASK_INTERRUPTS_ENABLED|MASK_KERNEL_UNLOCKED|MASK_NOT_ISR|MASK_NOT_IDFC|MASK_NO_FAST_MUTEX);
	ASM_ASSERT_DATA_PAGING_SAFE

	asm("mrs ip, spsr ");
	asm("tst ip, #0x0f ");
	asm("bne  " CSM_ZN5TDes89SetLengthEi);
	USER_MEMORY_GUARD_OFF(,r12,r12);
	asm("ldrt r2, [r0], #4 ");			// r2=length/type, r0->maxlength
	asm("ldrt r3, [r0], #-4 ");			// r3=maxlength, r0->length/type
	asm("and r2, r2, #0xf0000000 ");	// r2=type field
	asm("cmp r2, #0x20000000 ");		// check for writeable descriptor
	USER_MEMORY_GUARD_ON(cc,r12,r12);
	asm("bcc  " CSM_Z29KUDesSetLengthPanicBadDesTypev);
	asm("cmp r1, r3 ");					// check length
	USER_MEMORY_GUARD_ON(hi,r12,r12);
	asm("bhi  " CSM_Z27KUDesSetLengthPanicOverflowv);
	asm("cmp r2, #0x40000000 ");		// check for EBufCPtr
	asm("orr r2, r2, r1 ");				// r2=type + new length
	asm("strt r2, [r0], #8 ");			// store new length, r0->ptr if EBufCPtr
	USER_MEMORY_GUARD_ON(ne,r12,r12);
	__JUMP(ne,lr);						// if not EBufCPtr finished
	asm("ldrt r2, [r0] ");				// r2=pointer to TBufCBase
	asm("strt r1, [r2] ");				// update length of TBufCBase
	USER_MEMORY_GUARD_ON(,r12,r12);
	__JUMP(,lr);
  	}


/**
Checks whether the specified name is a valid Kernel-side object name.

A name is invalid, if it contains non-ascii characters, or any of
the three characters: "*", "?", ":".

@param  aName The name to be checked.

@return KErrNone, if the name is valid; KErrBadName, if the name is invalid.

@pre Calling thread can be either in a critical section or not.
@pre Interrupts must be enabled.
@pre Kernel must be unlocked.
@pre No fast mutex can be held.
@pre Call in a thread context.
@pre Can be used in a device driver.
*/
#ifndef __KERNEL_MODE__
#error "TDesC is not 8-bit as __KERNEL_MODE__ is not defined (see e32cmn.h)"
#endif
__NAKED__ EXPORT_C TInt Kern::ValidateName(const TDesC& /*aName*/)
//
// Check for : * or ? in descriptor, return KErrBadName if found
//
	{
	ASM_CHECK_PRECONDITIONS(MASK_INTERRUPTS_ENABLED|MASK_KERNEL_UNLOCKED|MASK_NOT_ISR|MASK_NOT_IDFC|MASK_NO_FAST_MUTEX);

	asm("ldr r2, [r0], #4 ");			// r2=length/type
	asm("cmp r2, #0x50000000 ");
	asm("bcs " CSM_Z19Des8PanicBadDesTypev );
	asm("bics r3, r2, #0xF0000000 ");	// r3=length
	asm("moveq r0, #0 ");				// if length=0, return KErrNone
	__JUMP(eq,lr);
	asm("eor r2, r2, r2, lsr #1 ");
	asm("msr cpsr_flg, r2 ");
	asm("addcs r0, r0, #4 ");
	asm("ldrle r0, [r0] ");
	asm("addeq r0, r0, #4 ");			// r0=this.Ptr()
	asm("1: ");
	asm("ldrb r1, [r0], #1 ");			// r1=*r0++
	asm("cmp r1, #0x20 ");				// is it < 0x20 ?
	asm("rsbhss r2, r1, #0x7f ");		// if not, compare 0x7f with char
	asm("bls 2f ");						// if char < 0x20 or 0x7f <= char, error
	asm("cmp r1, #'*' ");				// is it *
	asm("cmpne r1, #':' ");				// if not, is it :
	asm("cmpne r1, #'?' ");				// if not, is it ?
	asm("subnes r3, r3, #1 ");			// if none of these, decrement length
	asm("bne 1b ");
	asm("2: ");
	asm("cmp r3, #0 ");					// reached end of string?
	asm("moveq r0, #0 ");				// if we did, return KErrNone
	asm("mvnne r0, #%a0" : : "i" (~KErrBadName));	// else return KErrBadName
	__JUMP(,lr);
	}

extern "C" EXPORT_C __NAKED__ TInt memicmp(const TAny* /*aLeft*/, const TAny* /*aRight*/, TUint /*aLength*/)
    {
	// r0 = aLeft, r1 = aRight, r2 = aLength
	asm("str r4, [sp, #-4]! ");
	asm("add r2, r2, #1 ");

	asm("1: ");
	asm("subs r2, r2, #1 ");
	asm("ldrneb r3, [r0], #1 ");
	asm("beq 0f ");
	asm("ldrb r4, [r1], #1 ");
	asm("orr ip, r3, #0x20 ");
	asm("cmp ip, #0x61 ");
	asm("rsbcss ip, ip, #0x7a ");
	asm("eors ip, r3, r4 ");
	asm("andcss ip, ip, #0xdf ");
	asm("beq 1b ");
	asm("orrcs r3, r3, #0x20 ");
	asm("cmp r4, #0x41 ");
	asm("rsbcss ip, r4, #0x5a ");
	asm("orrcs r4, r4, #0x20 ");
	asm("subs r0, r3, r4 ");
	asm("0: ");
	asm("moveq r0, #0 ");
	asm("ldr r4, [sp], #4 ");
	__JUMP(,lr);
	}
#endif