8XC196LX SUPPLEMENT
prioritized interrupt | NMI, stack overflow, or any maskable interrupt. Two | |
| of the nonmaskable interrupts (unimplemented | |
| opcode and software trap) are not prioritized; they | |
| vector directly to the interrupt service routine when | |
| executed. | |
program memory | A partition of memory where instructions can be | |
| stored for fetching and execution. | |
protected instruction | An instruction that prevents an interrupt from being | |
| acknowledged until after the next instruction | |
| executes. The protected instructions are DI, EI, | |
| DPTS, EPTS, POPA, POPF, PUSHA, and PUSHF. | |
PSW | Processor status word. The high byte of the PSW is | |
| the status byte, which contains one bit that globally | |
| enables or disables servicing of all maskable | |
| interrupts, one bit that enables or disables the PTS, | |
| and six Boolean flags that reflect the state of the | |
| current program. The low byte of the PSW is the | |
| INT_MASK register. A PUSHA or POPA instruction | |
| saves or restores both bytes (PSW + INT_MASK); a | |
| PUSHF or POPF saves or restores only the PSW. | |
PTS | Peripheral transaction server. The microcoded | |
| hardware interrupt processor. | |
PTSCB | See PTS control block. | |
PTS control block | A block of data required for each PTS interrupt. The | |
| microcode executes the proper PTS routine based on | |
| the contents of the PTS control block. | |
PTS cycle | The microcoded response to a single PTS interrupt | |
| request. | |
PTS interrupt | Any maskable interrupt that is assigned to the PTS for | |
| interrupt processing. | |
PTS mode | A microcoded response that enables the PTS to | |
| complete a specific task quickly. | |
PTS routine | The entire microcoded response to multiple PTS | |
| interrupt requests. The PTS routine is controlled by | |
| the contents of the PTS control block. | |
PTS transfer | The movement of a single byte or word from the | |
| source memory location to the destination memory | |
| location. | |
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