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/*	$Id: cpu_mem.c,v 1.11 2004/02/20 16:09:04 monaka Exp $	*/

/*
 * Copyright (c) 2002-2003 NONAKA Kimihiro
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "compiler.h"
#include "cpu.h"
#include "memory.h"


/*
 * memory access check
 */
void
cpu_memoryread_check(descriptor_t *sd, UINT32 offset, UINT length, int e)
{
	UINT32 uplimit;

	if (CPU_STAT_PM) {
		/* invalid */
		if (!sd->valid) {
			VERBOSE(("cpu_memoryread_check: invalid"));
			EXCEPTION(GP_EXCEPTION, 0);
		}

		/* not present */
		if (!sd->p) {
			VERBOSE(("cpu_memoryread_check: not present"));
			EXCEPTION(e, 0);
		}
	}

	switch (sd->type) {
	case 0:	 case 1:	/* ro */
	case 2:  case 3:	/* rw */
	case 10: case 11:	/* rx */
	case 14: case 15:	/* rxc */
		if (offset > sd->u.seg.limit - length + 1) {
			VERBOSE(("cpu_memoryread_check: offset(%08x) > sd->u.seg.limit(%08x) - length(%08x) + 1", offset, sd->u.seg.limit, length));
			EXCEPTION(e, 0);
		}
		if (length - 1 > sd->u.seg.limit) {
			VERBOSE(("cpu_memoryread_check: length(%08x) - 1 > sd->u.seg.limit(%08x)", length, sd->u.seg.limit));
			EXCEPTION(e, 0);
		}
		break;

	case 4:  case 5:	/* ro (expand down) */
	case 6:  case 7:	/* rw (expand down) */
		uplimit = sd->d ? 0xffffffff : 0x0000ffff;
		if (offset <= sd->u.seg.limit) {
			VERBOSE(("cpu_memoryread_check: offset(%08x) <= sd->u.seg.limit(%08x)", offset, sd->u.seg.limit));
			EXCEPTION(e, 0);
		}
		if (offset > uplimit) {
			VERBOSE(("cpu_memoryread_check: offset(%08x) > uplimit(%08x)", offset, uplimit));
			EXCEPTION(e, 0);
		}
		if (uplimit - offset < length - 1) {
			VERBOSE(("cpu_memoryread_check: uplimit(%08x) - offset(%08x) < length(%08x) - 1", uplimit, offset, length));
			EXCEPTION(e, 0);
		}
		break;

	default:
		VERBOSE(("cpu_memoryread_check: invalid type (type = %d)", sd->type));
		EXCEPTION(e, 0);
		break;
	}
	sd->flag |= CPU_DESC_FLAG_READABLE;
}

void
cpu_memorywrite_check(descriptor_t *sd, UINT32 offset, UINT length, int e)
{
	UINT32 uplimit;

	if (CPU_STAT_PM) {
		/* invalid */
		if (!sd->valid) {
			VERBOSE(("cpu_memorywrite_check: invalid"));
			EXCEPTION(GP_EXCEPTION, 0);
		}

		/* not present */
		if (!sd->p) {
			VERBOSE(("cpu_memorywrite_check: not present"));
			EXCEPTION(e, 0);
		}

		if (!sd->s) {
			VERBOSE(("cpu_memorywrite_check: system segment"));
			EXCEPTION(e, 0);
		}
	}

	switch (sd->type) {
	case 2: case 3:	/* rw */
		if (offset > sd->u.seg.limit - length + 1) {
			VERBOSE(("cpu_memorywrite_check: offset(%08x) > sd->u.seg.limit(%08x) - length(%08x) + 1", offset, sd->u.seg.limit, length));
			EXCEPTION(e, 0);
		}
		if (length - 1 > sd->u.seg.limit) {
			VERBOSE(("cpu_memorywrite_check: length(%08x) - 1 > sd->u.seg.limit(%08x)", length, sd->u.seg.limit));
			EXCEPTION(e, 0);
		}
		break;

	case 6: case 7:	/* rw (expand down) */
		uplimit = sd->d ? 0xffffffff : 0x0000ffff;
		if (offset <= sd->u.seg.limit) {
			VERBOSE(("cpu_memorywrite_check: offset(%08x) <= sd->u.seg.limit(%08x)", offset, sd->u.seg.limit));
			EXCEPTION(e, 0);
		}
		if (offset > uplimit) {
			VERBOSE(("cpu_memorywrite_check: offset(%08x) > uplimit(%08x)", offset, uplimit));
			EXCEPTION(e, 0);
		}
		if (uplimit - offset < length - 1) {
			VERBOSE(("cpu_memorywrite_check: uplimit(%08x) - offset(%08x) < length(%08x) - 1", uplimit, offset, length));
			EXCEPTION(e, 0);
		}
		break;

	default:
		VERBOSE(("cpu_memorywrite_check: invalid type (type = %d)", sd->type));
		EXCEPTION(e, 0);
		break;
	}
	sd->flag |= CPU_DESC_FLAG_WRITABLE;
}

BOOL
cpu_stack_push_check(descriptor_t *sd, UINT32 esp, UINT length)
{
	UINT32 limit;

	if (CPU_STAT_PM) {
		if (!sd->valid || !sd->p)
			return FALSE;
		if (!sd->s || sd->u.seg.c || !sd->u.seg.wr)
			return FALSE;

		if (!sd->d) {
			esp &= 0xffff;
			limit = 0xffff;
		} else {
			limit = 0xffffffff;
		}
		if (sd->u.seg.ec) {
			/* expand-down stack */
			if ((esp == 0)
			 || (esp < length)
			 || (esp - length <= sd->u.seg.limit)
			 || (esp > limit))
				return FALSE;
		} else {
			/* expand-up stack */
			if (esp == 0) {
				if ((sd->d && (sd->u.seg.segend != 0xffffffff))
				 || (!sd->d && (sd->u.seg.segend != 0xffff)))
					return FALSE;
			} else {
				if ((esp < length)
				 || (esp - 1 > sd->u.seg.limit))
					return FALSE;
			}
		}
	}
	return TRUE;
}

BOOL
cpu_stack_pop_check(descriptor_t *sd, UINT32 esp, UINT length)
{
	UINT32 limit;

	if (CPU_STAT_PM) {
		if (!sd->valid || !sd->p)
			return FALSE;
		if (!sd->s || sd->u.seg.c || !sd->u.seg.wr)
			return FALSE;

		if (!sd->d) {
			esp &= 0xffff;
			limit = 0xffff;
		} else {
			limit = 0xffffffff;
		}
		if (sd->u.seg.ec) {
			/* expand-down stack */
			if ((esp == limit)
			 || ((limit - esp) + 1 < length))
				return FALSE;
		} else {
			/* expand-up stack */
			if ((esp == limit)
			 || (sd->u.seg.segend == 0)
			 || (esp > sd->u.seg.limit)
			 || ((sd->u.seg.limit - esp) + 1 < length))
				return FALSE;
		}
	}
	return TRUE;
}


/*
 * code fetch
 */
UINT8 MEMCALL
cpu_codefetch(UINT32 offset)
{
	descriptor_t *sd;
	UINT32 addr;

	sd = &CPU_STAT_SREG(CPU_CS_INDEX);
	if (offset <= sd->u.seg.limit) {
		addr = CPU_STAT_SREGBASE(CPU_CS_INDEX) + offset;
		if (!CPU_STAT_PM)
			return cpu_memoryread(addr);
		return cpu_lcmemoryread(addr);
	}
	EXCEPTION(GP_EXCEPTION, 0);
	return 0;	/* compiler happy */
}

UINT16 MEMCALL
cpu_codefetch_w(UINT32 offset)
{
	descriptor_t *sd;
	UINT32 addr;

	sd = &CPU_STAT_SREG(CPU_CS_INDEX);
	if (offset <= sd->u.seg.limit - 1) {
		addr = CPU_STAT_SREGBASE(CPU_CS_INDEX) + offset;
		if (!CPU_STAT_PM)
			return cpu_memoryread_w(addr);
		return cpu_lcmemoryread_w(addr);
	}
	EXCEPTION(GP_EXCEPTION, 0);
	return 0;	/* compiler happy */
}

UINT32 MEMCALL
cpu_codefetch_d(UINT32 offset)
{
	descriptor_t *sd;
	UINT32 addr;

	sd = &CPU_STAT_SREG(CPU_CS_INDEX);
	if (offset <= sd->u.seg.limit - 3) {
		addr = CPU_STAT_SREGBASE(CPU_CS_INDEX) + offset;
		if (!CPU_STAT_PM)
			return cpu_memoryread_d(addr);
		return cpu_lcmemoryread_d(addr);
	}
	EXCEPTION(GP_EXCEPTION, 0);
	return 0;	/* compiler happy */
}


/*
 * virtual address -> linear address
 */
UINT8 MEMCALL
cpu_vmemoryread(int idx, UINT32 offset)
{
	descriptor_t *sd;
	UINT32 addr;
	int exc;

	__ASSERT((unsigned int)idx < CPU_SEGREG_NUM);

	sd = &CPU_STAT_SREG(idx);
	if (!sd->valid) {
		exc = GP_EXCEPTION;
		goto err;
	}

	if (!(sd->flag & CPU_DESC_FLAG_READABLE)) {
		cpu_memoryread_check(sd, offset, 1,
		    (idx == CPU_SS_INDEX) ? SS_EXCEPTION : GP_EXCEPTION);
	} else {
		switch (sd->type) {
		case 4: case 5: case 6: case 7:
			if (offset <= sd->u.seg.limit) {
				if (idx == CPU_SS_INDEX)
					exc = SS_EXCEPTION;
				else
					exc = GP_EXCEPTION;
				goto err;
			}
			break;

		default:
			if (offset > sd->u.seg.limit) {
				if (idx == CPU_SS_INDEX)
					exc = SS_EXCEPTION;
				else
					exc = GP_EXCEPTION;
				goto err;
			}
			break;
		}
	}
	addr = CPU_STAT_SREGBASE(idx) + offset;
	if (!CPU_STAT_PM)
		return cpu_memoryread(addr);
	return cpu_lmemoryread(addr, CPU_STAT_USER_MODE);

err:
	EXCEPTION(exc, 0);
	return 0;	/* compiler happy */
}

UINT16 MEMCALL
cpu_vmemoryread_w(int idx, UINT32 offset)
{
	descriptor_t *sd;
	UINT32 addr;
	int exc;

	__ASSERT((unsigned int)idx < CPU_SEGREG_NUM);

	sd = &CPU_STAT_SREG(idx);
	if (!sd->valid) {
		exc = GP_EXCEPTION;
		goto err;
	}

	if (!(sd->flag & CPU_DESC_FLAG_READABLE)) {
		cpu_memoryread_check(sd, offset, 2,
		    (idx == CPU_SS_INDEX) ? SS_EXCEPTION : GP_EXCEPTION);
	} else {
		switch (sd->type) {
		case 4: case 5: case 6: case 7:
			if (offset - 1 <= sd->u.seg.limit) {
				if (idx == CPU_SS_INDEX)
					exc = SS_EXCEPTION;
				else
					exc = GP_EXCEPTION;
				goto err;
			}
			break;

		default:
			if (offset > sd->u.seg.limit - 1) {
				if (idx == CPU_SS_INDEX)
					exc = SS_EXCEPTION;
				else
					exc = GP_EXCEPTION;
				goto err;
			}
			break;
		}
	} 
	addr = CPU_STAT_SREGBASE(idx) + offset;
	if (!CPU_STAT_PM)
		return cpu_memoryread_w(addr);
	return cpu_lmemoryread_w(addr, CPU_STAT_USER_MODE);

err:
	EXCEPTION(exc, 0);
	return 0;	/* compiler happy */
}

UINT32 MEMCALL
cpu_vmemoryread_d(int idx, UINT32 offset)
{
	descriptor_t *sd;
	UINT32 addr;
	int exc;

	__ASSERT((unsigned int)idx < CPU_SEGREG_NUM);

	sd = &CPU_STAT_SREG(idx);
	if (!sd->valid) {
		exc = GP_EXCEPTION;
		goto err;
	}

	if (!(sd->flag & CPU_DESC_FLAG_READABLE)) {
		cpu_memoryread_check(sd, offset, 4,
		    (idx == CPU_SS_INDEX) ? SS_EXCEPTION : GP_EXCEPTION);
	} else {
		switch (sd->type) {
		case 4: case 5: case 6: case 7:
			if (offset - 3 <= sd->u.seg.limit) {
				if (idx == CPU_SS_INDEX)
					exc = SS_EXCEPTION;
				else
					exc = GP_EXCEPTION;
				goto err;
			}
			break;

		default:
			if (offset > sd->u.seg.limit - 3) {
				if (idx == CPU_SS_INDEX)
					exc = SS_EXCEPTION;
				else
					exc = GP_EXCEPTION;
				goto err;
			}
			break;
		}
	}
	addr = CPU_STAT_SREGBASE(idx) + offset;
	if (!CPU_STAT_PM)
		return cpu_memoryread_d(addr);
	return cpu_lmemoryread_d(addr, CPU_STAT_USER_MODE);

err:
	EXCEPTION(exc, 0);
	return 0;	/* compiler happy */
}

/* vaddr memory write */
void MEMCALL
cpu_vmemorywrite(int idx, UINT32 offset, UINT8 val)
{
	descriptor_t *sd;
	UINT32 addr;
	int exc;

	__ASSERT((unsigned int)idx < CPU_SEGREG_NUM);

	sd = &CPU_STAT_SREG(idx);
	if (!sd->valid) {
		exc = GP_EXCEPTION;
		goto err;
	}

	if (!(sd->flag & CPU_DESC_FLAG_WRITABLE)) {
		cpu_memorywrite_check(sd, offset, 1,
		    (idx == CPU_SS_INDEX) ? SS_EXCEPTION : GP_EXCEPTION);
	} else {
		switch (sd->type) {
		case 6: case 7:
			if (offset <= sd->u.seg.limit) {
				if (idx == CPU_SS_INDEX)
					exc = SS_EXCEPTION;
				else
					exc = GP_EXCEPTION;
				goto err;
			}
			break;

		default:
			if (offset > sd->u.seg.limit) {
				if (idx == CPU_SS_INDEX)
					exc = SS_EXCEPTION;
				else
					exc = GP_EXCEPTION;
				goto err;
			}
			break;
		}
	}
	addr = CPU_STAT_SREGBASE(idx) + offset;
	if (!CPU_STAT_PM) {
		/* real mode */
		cpu_memorywrite(addr, val);
	} else {
		/* protected mode */
		cpu_lmemorywrite(addr, val, CPU_STAT_USER_MODE);
	}
	return;

err:
	EXCEPTION(exc, 0);
}

void MEMCALL
cpu_vmemorywrite_w(int idx, UINT32 offset, UINT16 val)
{
	descriptor_t *sd;
	UINT32 addr;
	int exc;

	__ASSERT((unsigned int)idx < CPU_SEGREG_NUM);

	sd = &CPU_STAT_SREG(idx);
	if (!sd->valid) {
		exc = GP_EXCEPTION;
		goto err;
	}

	if (!(sd->flag & CPU_DESC_FLAG_WRITABLE)) {
		cpu_memorywrite_check(sd, offset, 2,
		    (idx == CPU_SS_INDEX) ? SS_EXCEPTION : GP_EXCEPTION);
	} else {
		switch (sd->type) {
		case 6: case 7:
			if (offset - 1 <= sd->u.seg.limit) {
				if (idx == CPU_SS_INDEX)
					exc = SS_EXCEPTION;
				else
					exc = GP_EXCEPTION;
				goto err;
			}
			break;

		default:
			if (offset > sd->u.seg.limit - 1) {
				if (idx == CPU_SS_INDEX)
					exc = SS_EXCEPTION;
				else
					exc = GP_EXCEPTION;
				goto err;
			}
			break;
		}
	}
	addr = CPU_STAT_SREGBASE(idx) + offset;
	if (!CPU_STAT_PM) {
		/* real mode */
		cpu_memorywrite_w(addr, val);
	} else {
		/* protected mode */
		cpu_lmemorywrite_w(addr, val, CPU_STAT_USER_MODE);
	}
	return;

err:
	EXCEPTION(exc, 0);
}

void MEMCALL
cpu_vmemorywrite_d(int idx, UINT32 offset, UINT32 val)
{
	descriptor_t *sd;
	UINT32 addr;
	int exc;

	__ASSERT((unsigned int)idx < CPU_SEGREG_NUM);

	sd = &CPU_STAT_SREG(idx);
	if (!sd->valid) {
		exc = GP_EXCEPTION;
		goto err;
	}

	if (!(sd->flag & CPU_DESC_FLAG_WRITABLE)) {
		cpu_memorywrite_check(sd, offset, 4,
		    (idx == CPU_SS_INDEX) ? SS_EXCEPTION : GP_EXCEPTION);
	} else {
		switch (sd->type) {
		case 6: case 7:
			if (offset - 3 <= sd->u.seg.limit) {
				if (idx == CPU_SS_INDEX)
					exc = SS_EXCEPTION;
				else
					exc = GP_EXCEPTION;
				goto err;
			}
			break;

		default:
			if (offset > sd->u.seg.limit - 3) {
				if (idx == CPU_SS_INDEX)
					exc = SS_EXCEPTION;
				else
					exc = GP_EXCEPTION;
				goto err;
			}
			break;
		}
	}
	addr = CPU_STAT_SREGBASE(idx) + offset;
	if (!CPU_STAT_PM) {
		/* real mode */
		cpu_memorywrite_d(addr, val);
	} else {
		/* protected mode */
		cpu_lmemorywrite_d(addr, val, CPU_STAT_USER_MODE);
	}
	return;

err:
	EXCEPTION(exc, 0);
}