Direct Mode - Revision history

Mr z: Protected "Direct Mode" ([edit=autoconfirmed] (indefinite) [move=autoconfirmed] (indefinite))

2010-12-04T08:14:15Z

Protected "Direct Mode" ([edit=autoconfirmed] (indefinite) [move=autoconfirmed] (indefinite))

Mr z at 14:36, 15 January 2005

2005-01-15T14:36:11Z

Pingaso at 21:18, 14 January 2005

2005-01-14T21:18:22Z

Mr z at 20:05, 12 January 2005

2005-01-12T20:05:27Z

New page

[[Direct Mode]] accesses directly specify the address to read or write in the single word following the instruction. The range of addresses a [[Direct Mode]] instruction can access is a function of the width of the ROM that contains the object code.

[[Direct Mode]] instructions rely on the ADAR (Addressed Data to Address Register) [[Bus Phases|Bus Phase]] to inform the system of the address to access. Ordinarily, the programmer need not be aware of this detail. However, the System RAM does not correctly implement the ADAR [[Bus Phases|Bus Phase]]--it treats it as equivalent to the BAR (Bus to Address Register) [[Bus Phases|Bus Phase]]. Therefore, program code loaded into System RAM must not use [[Direct Mode]] instructions, as they will not function correctly.

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-Direct Mode accesses directly specify the address to read or write in the single word following the instruction.  The range of addresses a [[Direct Mode]] instruction can access is a function of the width of the ROM that contains the object code.
+Direct Mode accesses directly specify the address to read or write in the single word following the instruction.  The range of addresses a Direct Mode instruction can access is a function of the width of the ROM that contains the object code.
-Direct Mode instructions rely on the ADAR (Addressed Data to Address Register) [[Bus Phases|Bus Phase]] to inform the system of the address to access.  Ordinarily, the programmer need not be aware of this detail.  However, the System RAM does not correctly implement the ADAR [[Bus Phases|Bus Phase]]--it treats it as equivalent to the BAR (Bus to Address Register) [[Bus Phases|Bus Phase]].  Therefore, program code loaded into System RAM must not use [[Direct Mode]] instructions, as they will not function correctly.
+Direct Mode instructions rely on the ADAR (Addressed Data to Address Register) [[Bus Phases|Bus Phase]] to inform the system of the address to access.  Ordinarily, the programmer need not be aware of this detail.  However, the System RAM does not correctly implement the ADAR [[Bus Phases|Bus Phase]]--it treats it as equivalent to the BAR (Bus to Address Register) [[Bus Phases|Bus Phase]].  Therefore, program code loaded into System RAM must not use Direct Mode instructions, as they will not function correctly.
 The following are Direct Mode instructions.

← Older revision		Revision as of 21:18, 14 January 2005
Line 1:		Line 1:
−	[[Direct Mode]] accesses directly specify the address to read or write in the single word following the instruction. The range of addresses a [[Direct Mode]] instruction can access is a function of the width of the ROM that contains the object code.	+	Direct Mode accesses directly specify the address to read or write in the single word following the instruction. The range of addresses a [[Direct Mode]] instruction can access is a function of the width of the ROM that contains the object code.

−	[[Direct Mode]] instructions rely on the ADAR (Addressed Data to Address Register) [[Bus Phases\|Bus Phase]] to inform the system of the address to access. Ordinarily, the programmer need not be aware of this detail. However, the System RAM does not correctly implement the ADAR [[Bus Phases\|Bus Phase]]--it treats it as equivalent to the BAR (Bus to Address Register) [[Bus Phases\|Bus Phase]]. Therefore, program code loaded into System RAM must not use [[Direct Mode]] instructions, as they will not function correctly.	+	Direct Mode instructions rely on the ADAR (Addressed Data to Address Register) [[Bus Phases\|Bus Phase]] to inform the system of the address to access. Ordinarily, the programmer need not be aware of this detail. However, the System RAM does not correctly implement the ADAR [[Bus Phases\|Bus Phase]]--it treats it as equivalent to the BAR (Bus to Address Register) [[Bus Phases\|Bus Phase]]. Therefore, program code loaded into System RAM must not use [[Direct Mode]] instructions, as they will not function correctly.
		+
		+	The following are Direct Mode instructions.
		+
		+	[[MVO]]<br/>
		+	[[MVI]]<br/>
		+	[[ADD]]<br/>
		+	[[SUB]]<br/>
		+	[[CMP]]<br/>
		+	[[AND]]<br/>
		+	[[XOR]]<br/>

← Older revision	Revision as of 08:14, 4 December 2010
(No difference)