SP (A008) | Temporary storage location for the stack pointer. SP is used in the register |
| dump subroutines and by the breakpoint function. |
PORADD (A00A) | This location contains the port address used for SWTBUG’s I/O routines. |
PORECH (A00C) | This byte tells SWTBUG® ‘s input routines whether or not to echo. |
XHI (A00D) | Temporary index register storage used by numerous routines. |
XLOW (A00E) | Temporary index register storage used by numerous routines. |
XTEMP (A010) | Temporary index register storage for input and output routines. |
SWIJMP (A012) | When a SWI instruction is encountered, processor control will transfer to the |
| location stored in SWIJMP. |
BKPT (AQ14) | Temporary breakpoint address storage. |
BKLST (A016) | Temporary data storage for the breakpoint routine. |
TW (A044) | Temporary storage location for load/punch. |
TEMP (A046) | Temporary storage location for punch and load. |
BYTECT (A047) | Temporary storage location for load/punch. |
SWTBUG® SUBROUTINE AND TEXT STRING DESCRIPTION
IRQV (E000) | This is the entry point for regular IRQ interrupts. Processor control is given of | |
| the service routine whose address is stored in IRQ. | |
JUMP (E005) | This is the service routine for the J command. BADDR is used to input the | |
| address and a jump then occurs to the correct address. | |
CURSOR (E009) | ||
LOAD (E00C) | Load is the ASCII loading routine. Load uses a number of other SWTBUG® | |
| subroutines. |
|
BADDR (E047) | BADDR is a subroutine to input a | |
| from the control terminal. BADDR uses the subroutines BYTE, INCH and | |
| INHEX and uses temporary storage locations XHI, XLOW, CKSM, both | |
| accumulators and the index register. When BADDR is called it will look for | |
| four hex numbers to be entered from the terminal. If a | |
| as H, is entered, SWTBUG® control will resume. If all characters entered are | |
| valid hex, the results will be stored in XHI, XLOW and the index register. | |
| Accumulator A will contain of XLOW. If 137D is entered the results will be as | |
| follows- |
|
| ACC A | 7D |
| ACC B | CKSM |
| IXR | 137D |
| XHI | 13 |
| XLOW | 7D |
- | CKSM and ACC B are used internally to generate a check sum for the | |
| PUNCH routine. |
|
BYTE (E055) | BYTE is similar to BADDR, but inputs only two hex characters from the | |
| terminal to generate one | |
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