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Fix SGDT/SIDT for the 80386

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This commit is contained in:
Jeff Parsons 2015-11-23 17:07:56 -08:00
commit 10d2551bc0
2 changed files with 104 additions and 82 deletions
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74
docs/pcjs/demos/components.xsl
View file

@ -454,47 +454,45 @@
</xsl:template>
<xsl:template match="manifest[not(@ref)]" mode="component">
<xsl:param name="disk"><xsl:value-of select="@disk"/></xsl:param>
<xsl:if test="$disk != ''">
<xsl:variable name="prefix">
<xsl:if test="title/@prefix"><xsl:value-of select="title/@prefix"/><xsl:text>: </xsl:text></xsl:if>
</xsl:variable>
<xsl:for-each select="disk">
<xsl:if test="$disk = @id or $disk = '*'">
<xsl:variable name="name">
<xsl:choose>
<xsl:when test="name"><xsl:value-of select="$prefix"/><xsl:value-of select="name"/></xsl:when>
<xsl:when test="normalize-space(./text()) != ''">
<xsl:value-of select="$prefix"/><xsl:value-of select="normalize-space(./text())"/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="../title"/><xsl:if test="../version != ''"><xsl:text> </xsl:text><xsl:value-of select="../version"/></xsl:if>
</xsl:otherwise>
</xsl:choose>
</xsl:variable>
<xsl:variable name="link">
<xsl:if test="link">
<xsl:text>desc:'</xsl:text><xsl:value-of select="link"/><xsl:text>'</xsl:text>
<xsl:if test="link/@href">
<xsl:text>,href:'</xsl:text><xsl:value-of select="link/@href"/><xsl:text>'</xsl:text>
</xsl:if>
<xsl:param name="disk"><xsl:if test="@disk"><xsl:value-of select="@disk"/></xsl:if><xsl:if test="not(@disk)">*</xsl:if></xsl:param>
<xsl:variable name="prefix">
<xsl:if test="title/@prefix"><xsl:value-of select="title/@prefix"/><xsl:text>: </xsl:text></xsl:if>
</xsl:variable>
<xsl:for-each select="disk">
<xsl:if test="$disk = @id or $disk = '*'">
<xsl:variable name="name">
<xsl:choose>
<xsl:when test="name"><xsl:value-of select="$prefix"/><xsl:value-of select="name"/></xsl:when>
<xsl:when test="normalize-space(./text()) != ''">
<xsl:value-of select="$prefix"/><xsl:value-of select="normalize-space(./text())"/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="../title"/><xsl:if test="../version != ''"><xsl:text> </xsl:text><xsl:value-of select="../version"/></xsl:if>
</xsl:otherwise>
</xsl:choose>
</xsl:variable>
<xsl:variable name="link">
<xsl:if test="link">
<xsl:text>desc:'</xsl:text><xsl:value-of select="link"/><xsl:text>'</xsl:text>
<xsl:if test="link/@href">
<xsl:text>,href:'</xsl:text><xsl:value-of select="link/@href"/><xsl:text>'</xsl:text>
</xsl:if>
</xsl:variable>
<xsl:if test="@href">
<option value="{@href}" data-value="{$link}"><xsl:value-of select="$name"/></option>
</xsl:if>
<xsl:if test="not(@href)">
<xsl:variable name="dir">
<xsl:if test="@dir"><xsl:value-of select="@dir"/></xsl:if>
</xsl:variable>
<xsl:variable name="files">
<xsl:for-each select="file"><xsl:if test="position() = 1"><xsl:value-of select="$dir"/></xsl:if><xsl:value-of select="@dir"/><xsl:value-of select="."/><xsl:if test="position() != last()">;</xsl:if></xsl:for-each>
</xsl:variable>
<option value="{$files}" data-value="{$link}"><xsl:value-of select="$name"/></option>
</xsl:if>
</xsl:variable>
<xsl:if test="@href">
<option value="{@href}" data-value="{$link}"><xsl:value-of select="$name"/></option>
</xsl:if>
</xsl:for-each>
</xsl:if>
<xsl:if test="not(@href)">
<xsl:variable name="dir">
<xsl:if test="@dir"><xsl:value-of select="@dir"/></xsl:if>
</xsl:variable>
<xsl:variable name="files">
<xsl:for-each select="file"><xsl:if test="position() = 1"><xsl:value-of select="$dir"/></xsl:if><xsl:value-of select="@dir"/><xsl:value-of select="."/><xsl:if test="position() != last()">;</xsl:if></xsl:for-each>
</xsl:variable>
<option value="{$files}" data-value="{$link}"><xsl:value-of select="$name"/></option>
</xsl:if>
</xsl:if>
</xsl:for-each>
</xsl:template>
<xsl:template match="name">

112
modules/pcjs/lib/x86func.js
View file

@ -2883,57 +2883,77 @@ X86.fnSGDT = function(dst, src)
X86.opInvalid.call(this);
} else {
/*
* We don't need to setShort() the first word of the operand, because the ModRM group decoder that
* calls us does that automatically with the value we return (dst).
* We don't need to set the first word of the operand, because the ModRM group decoder that calls us
* does that automatically with the value we return (dst).
*/
dst = this.addrGDTLimit - this.addrGDT;
this.assert(!(dst & ~0xffff));
/*
* We previously left the 6th byte of the target operand "undefined". But it turns out we have to set
* it to *something*, because there's processor detection in PC-DOS 7.0 (at least in the SETUP portion)
* that looks like this:
*
* 145E:4B84 9C PUSHF
* 145E:4B85 55 PUSH BP
* 145E:4B86 8BEC MOV BP,SP
* 145E:4B88 B80000 MOV AX,0000
* 145E:4B8B 50 PUSH AX
* 145E:4B8C 9D POPF
* 145E:4B8D 9C PUSHF
* 145E:4B8E 58 POP AX
* 145E:4B8F 2500F0 AND AX,F000
* 145E:4B92 3D00F0 CMP AX,F000
* 145E:4B95 7511 JNZ 4BA8
* 145E:4BA8 C8060000 ENTER 0006,00
* 145E:4BAC 0F0146FA SGDT [BP-06]
* 145E:4BB0 807EFFFF CMP [BP-01],FF
* 145E:4BB4 C9 LEAVE
* 145E:4BB5 BA8603 MOV DX,0386
* 145E:4BB8 7503 JNZ 4BBD
* 145E:4BBA BA8602 MOV DX,0286
* 145E:4BBD 89163004 MOV [0430],DX
* 145E:4BC1 5D POP BP
* 145E:4BC2 9D POPF
* 145E:4BC3 CB RETF
*
* This code is expecting SGDT on an 80286 to set the 6th "undefined" byte to 0xFF.
*
* The 80386 adds an additional wrinkle: the 6th byte must be 0x00 if the OPERAND size is 2, whereas
* it must passed through if the OPERAND size is 4.
*
* In addition, when the OPERAND size is 4, the ModRM group decoder will call setLong(dst) rather than
* setShort(dst); we could fix that by forcing the dataSize to 2, but it seems simpler to set the high
* bits (16-31) of dst to match the low bits (0-15) of addr, so that the caller will harmlessly rewrite
* what we already wrote with the setLong() below.
*/
var addr = this.addrGDT;
if (this.model == X86.MODEL_80286) {
/*
* We previously left the 6th byte of the target operand "undefined". But it turns out we have to set
* it to *something*, because there's processor detection in PC-DOS 7.0 (at least in the SETUP portion)
* that looks like this:
*
* 145E:4B84 9C PUSHF
* 145E:4B85 55 PUSH BP
* 145E:4B86 8BEC MOV BP,SP
* 145E:4B88 B80000 MOV AX,0000
* 145E:4B8B 50 PUSH AX
* 145E:4B8C 9D POPF
* 145E:4B8D 9C PUSHF
* 145E:4B8E 58 POP AX
* 145E:4B8F 2500F0 AND AX,F000
* 145E:4B92 3D00F0 CMP AX,F000
* 145E:4B95 7511 JNZ 4BA8
* 145E:4BA8 C8060000 ENTER 0006,00
* 145E:4BAC 0F0146FA SGDT [BP-06]
* 145E:4BB0 807EFFFF CMP [BP-01],FF
* 145E:4BB4 C9 LEAVE
* 145E:4BB5 BA8603 MOV DX,0386
* 145E:4BB8 7503 JNZ 4BBD
* 145E:4BBA BA8602 MOV DX,0286
* 145E:4BBD 89163004 MOV [0430],DX
* 145E:4BC1 5D POP BP
* 145E:4BC2 9D POPF
* 145E:4BC3 CB RETF
*
* This code is expecting SGDT on an 80286 to set the 6th "undefined" byte to 0xFF, so that's what we do.
*/
addr |= (0xff000000|0);
}
else if (this.model >= X86.MODEL_80386) {
/*
* The 80386 added another wrinkle: Intel's documentation claimed that the 6th byte is either set to zero
* or the high byte of the BASE field, depending on the OPERAND size; from the "INTEL 80386 PROGRAMMER'S
* REFERENCE MANUAL 1986":
*
* The LIMIT field of the [GDTR or IDTR] register is assigned to the first word at the effective address.
* If the operand-size attribute is 32 bits, the next three bytes are assigned the BASE field of the
* register, and the fourth byte is written with zero. The last byte is undefined. Otherwise, if the
* operand-size attribute is 16 bits, the next 4 bytes are assigned the 32-bit BASE field of the register.
*
* However, Intel obviously meant the reverse (ie, that the BASE field is truncated when using a 16-bit
* OPERAND size, not when using a 32-bit OPERAND size).
*
* UPDATE: Thanks to Michal Necasek, we now know that the: "386 in reality does not pay attention to the
* operand size (despite Intel's claims to the contrary). In fact Windows 3.11/Win32s relies on it -- at least
* in some configurations, it will execute SGDT in 16-bit code and will crash if all 6 bytes aren't stored."
*/
if (this.sizeData == 2) {
addr &= 0x00ffffff;
/*
* Based on the above information, we no longer mask the 6th byte on the 80386 when the OPERAND size is 2.
*
* addr &= 0x00ffffff;
*/
} else {
/*
* When the OPERAND size is 4, our ModRM group decoder will call setLong(dst) rather than setShort(dst);
* we could fix that by calling setDataSize(2), but it seems safer/simpler to set the high bits (16-31)
* of dst to match the low bits (0-15) of addr, so that the caller will harmlessly rewrite what we are
* already writing with the setLong() below.
*/
dst |= (addr << 16);
}
}
@ -3277,8 +3297,8 @@ X86.fnSIDT = function(dst, src)
X86.opInvalid.call(this);
} else {
/*
* We don't need to setShort() the first word of the operand, because the ModRM group decoder that calls
* us does that automatically with the value we return (dst).
* We don't need to set the first word of the operand, because the ModRM group decoder that calls us
* does that automatically with the value we return (dst).
*/
dst = this.addrIDTLimit - this.addrIDT;
this.assert(!(dst & ~0xffff));
@ -3292,7 +3312,11 @@ X86.fnSIDT = function(dst, src)
}
else if (this.model >= X86.MODEL_80386) {
if (this.sizeData == 2) {
addr &= 0x00ffffff;
/*
* Based on the SGDT information above, we no longer mask the 6th byte when the OPERAND size is 2.
*
* addr &= 0x00ffffff;
*/
} else {
dst |= (addr << 16);
}