Specifications

Intel
®
Quark SoC X1000 Core
October 2013 Developer’s Manual
Order Number: 329679-001US 35
Architectural Overview—Intel
®
Quark Core
The IF bit in the EFLAG registers is reset when an interrupt is being serviced. This
effectively disables servicing additional interrupts during an interrupt service routine.
However, the IF may be set explicitly by the interrupt handler, to allow the nesting of
interrupts. When an IRET instruction is executed, the original state of the IF is restored.
3.7.4 Non-Maskable Interrupt
Non-maskable interrupts provide a method of servicing very high priority interrupts. A
common example of the use of a non-maskable interrupt (NMI) would be to activate a
power failure routine or SMI# to activate a power saving mode. When the NMI input is
pulled high, it causes an interrupt with an internally supplied vector value of 2. Unlike a
normal hardware interrupt, no interrupt acknowledgment sequence is performed for an
NMI.
Table 5. Interrupt Vector Assignments
Function
Interrupt
Number
Instruction that can cause
exception
Return Address
Points to Faulting
Instruction
Type
Divide Error 0 DIV, IDIV YES FAULT
Debug Exception 1 Any instruction YES TRAP†
NMI Interrupt 2 INT 2 or NMI NO NMI
One Byte Interrupt 3 INT NO TRAP
Interrupt on Overflow 4 INTO NO TRAP
Array Bounds Check 5 BOUND YES FAULT
Invalid OP-Code 6 Any illegal instruction YES FAULT
Device Not Available 7 ESC, WAIT YES FAULT
Double Fault 8
Any instruction that can
generate an exception
ABORT
Intel Reserved 9
Invalid TSS 10 JMP, CALL, IRET, INT YES FAULT
Segment Not Present 11 Segment Register Instructions YES FAULT
Stack Fault 12 Stack References YES FAULT
General Protection Fault 13 Any Memory Reference YES FAULT
Page Fault 14
Any Memory Access or Code
Fetch
YES FAULT
Intel Reserved 15
Alignment Check Interrupt 17 Unaligned Memory Access YES FAULT
Intel Reserved 18–31
Two Byte Interrupt 0–255 INT n NO TRAP
†Some debug exceptions may report both traps on the previous instruction, and faults on the next instruction.
Table 6. FPU Interrupt Vector Assignments
Function
Interrupt
Number
Instruction that can
cause exception
Return Address Points to
Faulting Instruction
Type
Floating-Point Error 16 Floating-point, WAIT YES FAULT