Hardware Register Commands

This section presents the keywords used in the ICE-88 emulator to refer to the following types of hardware registers and signals.

• 8088 Processor Register

• 8088 Status Flags

• ICE-88 Status Registers

• 8088 Pin Signals

The following commands that refer to hardware registers and signals are discuss-ed in this section.

Command Purpose

Set Register Set (change) the contents of any of the writeable 8088 registers.

RESET HARDWARE Reset ICE-88 hardware to initial state.

Discussion

Tables 7-1 through 7-6 show the tokens used to refer to any 8088 8-bit register, 16-bit register or pin signal.

Meta-term Class of tokens

general-register 16-bit and 8-bit work registers pointer-register 16-bit pointer registers index -register 16-bit index registers

segment-register 16-bit segment reference registers status-register 8- and 16-bit status registers pin-reference 8088 pin signals

flag-reference 8088 status flags

Table 7-1. 8088 General Registers

reference 8088 Register and Interpretation RAX 16-bit Accumulator

RAH High 8 bits of Accumulator RAL Low 8 bits of Accumulator RBX 16-bit Base Register RBH High 8 bits of Base Register RBL Low 8 bits of Base Register RCX 16-bit Count Register RCH High 8 bits of Count Register RCL Low 8 bits of Count Register RDX 16-bit Data Register RDH High 8 bits of Data Register RDL Low 8 bits of Data Register

ICE-88

ICE-88 Interrogation and Utility Commands

Table 7-2. Pointer Registers

reference 8088 Register and Interpretation SP 16-bit Stack Pointer

BP 16-bit Base Pointer

Table 7-3. Index Registers

reference 8088 Register and Interpretation SI 16-bit Source Index

01 16-bit Destination Register

Table 7-4. Segment Registers

reference 8088 Register and Interpretation CS 16-bit Code Segment Register OS 16-bit Data Segment Register SS 16-bit Stack Segment Register ES 16-bit Extra Segment Register

Table 7-5. Status Registers

reference Register and Interpretation IP 16-bit Instruction Pointer Register

RF 16-bit Flag Register

CAUSE (Read only) 8-bit Cause of last break in emulation OPCODE (Read only) 8-bit Previous opcode executed

PIP (Read only) 16-bit Previous Instruction Pointer Register TIMER (Read only) Low 16 bits of emulation timer

HTIMER (Read only) High 16 bits of emulation timer BUFFERSIZE (Read only) 16-bit trace buffer size Register LOWER (Read only) 16-bit Intellec address register UPPER (Read only) 16-bit Intellec address register

(displayed in decimal only)

Interrogation and Utility Commands

7-16

Table 7-6. Pin References

reference 8088 Pin (Read only)

ROY READY

NMI NMI

TEST TEST

HOLD HOLD

RST RESET

MN MN/MN (minimum/maximum configuration)

IR INTR

Table 7-7. Flag References

reference Flag

AFL Auxiliary-carry out of low byte to high byte CFL Carry or borrow out of high byte

DFL Direction of string manipulation instruction IFL Interrupt-enable (external)

OFL Overflow flag in signed arithmetic

PFL Parity

SFL Sign of the result of an operation

TFL Trap used to place processor in single step mode for debug

ZFL Zero indicates a zero value result of an operation

To set (change) the content of one of the processor registers, use a command with the form:

reference

=

Where expr is a numerical constant or numerical expression giving the desired new contents. Each of the registers that can be changed with this command has a definite size (16, 8, or 1 bits). If the new contents represents fewer bits than the destination register, the bits are right -justified in the register, and the remaining bits are set to zero. In other words the ICE-88 emulator assumes that the quantity represents the lowest-order bits, and sets any unspecified high-order bits to zero.

The RESET HARDWARE command is used to restore the ICE-88 hardware to the initial program load condition. One use for this command might be to reset the hardware when reconfiguring. The EXIT command includes the RESET HARD-W ARE function.

ICE-88

ICE-88 Interrogation and Utility Commands

When a RESET HARDW ARE command is issued, the ICE-88 emulator attempts to reset the hardware without disturbing any internal controls or user specified setup (breakpoints, map, or enable/disable trace conditionally). If this attempt is suc-cessful, the ICE-88 emulator returns a prompt to the user immediately:

*CLOCK = INTERNAL

* RESET HARDWARE ;This reset will not encounter any problems.

;Prompt appears immediately, no internal setup

;affected.

The user may now continue his processing.

If, however, this attempt is unsuccessful, the ICE-88 emulator will warn the user that it is beginning to reinitialize the hardware. It then attempts to reset the hard-ware by using initialization procedures and then restoring internal controls and setup to the pre-reset state (trace, however, cannot be restored to its previous state, and will be enabled unconditionally). Although no internal registers or flags are changed, the integrity of user memory, ICE memory, and current disk-mapped memory cannot be guaranteed. If this attempt to reset the hardware is successful, the ICE-88 emulator will return a warning to the user that the hardware has been initialized followed by a prompt. The user may then examine memory for integrity, reload memory or continue processing.

NOTE

If the above reinitialization is successful, the ICE-88 emulator may require up to approximately 30 seconds to fully restore the map.

If the ICE-88 emulator detects an error during this attempt, it will return an error message and a prompt to the user. No warning that the hardware has been reinitialized will be returned. The user should attempt to resolve the error condition and MUST reissue the RESET HARDWARE command. The ICE-88 emulator will then go through the reinitialization as described above. The following example illustrates the procedure required to respond to an error condition:

*CLOCK = EXTERNAL ERR 40:NO USER CLOCK

*RESET HARDWARE

WARN C8:REINITIALIZING - FAULT ERR 40:NO USER CLOCK

*CLO= INT

*RESET HARDWARE

WARN C8:REINITIALIZING FAULT WARN C6:HARDWARE REINITIALIZED

;This command forces an error condition.

;Error respo·nse.

;Not able to reset, tries to reinitialize.

;Reports an error and no warning that hardware was reinitialized; thus, reinitialization was not able to complete. The user must clear the error condition and then reset the hardware again in

;order to get the hardware into a known state.

;Clears the error condition, must reset again.

;This reset must clear the incomplete reset from

;above.

;Note that the user is informed that the hardware

;has been reinitialized and that the user specified

;setup (map, breakpoints, etc.) has been restored.

;Memory contents (ICE memory, user memory,

;and current disk-mapped memory) cannot be guaranteed. The user must verify the contents or reload his code and data.

Interrogation and Utility Commands

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