Southwest Specialty Products 6800 manual BIT no Label Condition Code, Bit

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The condition codes are as defined below:

BIT NO.

LABEL

CONDITION CODE

0

C

Carry-borrow

1

V

Overflow

2

Z

Zero

3

N

Negative

4

I

Interrupt mask

5

H

Half carry

In the above example the condition code of "3C" can be interpreted as follows:

3C16 =

0

0

1

1

1

1

0

0

 

BIT 7

BIT 6

BIT 5

BIT 4

BIT 3

BIT 2

BIT 1

BIT 0

Below are two examples of how the R command works. Assume that this small program was entered to change certain registers.

$M 0100

 

 

$0100 CE

8E

LOADS STACK POINTER TO 100

$0101 12

10

 

$0102 34

00

 

$0103 86

CE

LOAD INDEX REGISTER WITH 1234

$0104 00

12

 

$0105 C6

34

 

$0106 FF

86

LOAD ACCUMULATOR A WITH 00

$0107 FD

00

 

$0108 08

C6

LOAD ACCUMULATOR B WITH FF

$0109 23

FF

 

$010A

67

7E

JUMP BACK TO SWTBUG CONTROL

$010B

F7

E0

 

$010C

60

E3

 

$010D

DD

 

 

AT THIS POINT THE STATUS WILL NOT BE PUSHED ON THE STACK

4

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Contents ROM Monitor Verson Users Guide Swtpc Swtbug Swatbug Monitor ROM Swtbug Operation Swtbug InstallationReset Register Dump Function R Memory Examine and Change M addrBIT BIT no Label Condition CodeAscii Tape Punch Command P CT-1024 Clear Screen Command CGO to USER’S Program Function G Jump to USER’S Program JaddrMost Significant Byte of Lower Address END of Tape Command ELeast Significant Byte of Lower Address Most Significant Byte of Upper AddressSoftware Breakpoints Baddr Optional Port Command O not zeroTape Loader Function L Do not This is OK Disk Boot DJump to Prom Program Z Byte Search F high address low address byteUsing Maskable IRQ Interrupts Using NON-MASKABLE InterruptsVectored Software Interrupts Vectored INPUT/OUTPUTBaud Rate PIA StrobingUse of the Control Interface for Read/Punch-On/Off Decoding Loading Binary Tapes Thru Swtbug CompatibilityCO-RES Ver .0 and 1.01 Acia Modifications Special Notes on Using AN Acia and Program ModificationsBlkjak Swtpc 6800 Black Jack Program General Rules for Program Writing Memory DiagnosticsProgram Description Temporary Storage LocationsSwtbug Subroutine and Text String Description Outhr E06B ACC a ACC B Cksm IXR UnchangedOutee LDA aFCC /HELLO Start LDX #TEXT JSR PDATA1 JMP Contrl TextFCB ENDNmiv E1A7 Contrl E0E3Search E1AE Goto E1D0Break E2D9 Clear E2CCPNCHS9 E31E Pnchon E34D