Owner`s manual

Table 4–5: Machine Check Parameters

Parameter Description

Parameter Byte Count The size of thestack frame in bytes, not including PSL, PC, and the

byte count longword. It is always 18 (hex) bytes. Stack frame PC

and PSL values are always referenced using this count as an off-

set from the stack pointer.

R (VAX Restart bit) A ﬂag from the hardware and microcode to the operat-

ing system to be used in the software equation to deter-

mine if the current macroinstruction is restartable after er-

ror cleanup. Other terms in the equation are PSL<27> (First

Part Done, FPD), PCSTS<6> (Trap2), and XBEER0<11> (Un-

lock Write Pending, UWP). If R=1, no state has been changed

by the instruction that was executing when the error was de-

tected. If R=0, state had been changed by the instruc-

tion.

Machine check code

(bits<15:0>)

Table 4–6 lists and describes the machine check codes.

VA The virtual address being processed by the CPU at the

time of the fault. VA is not necessarily relevant; the er-

ror handler checks the speciﬁc error address correspond-

ing to the device or mechanism that signaled the er-

ror.

VIBA The CPU prefetch virtual instruction buffer address at the time of

the fault.

ICCS..SISR The interrupt state information where bit<22> is ICCS<6> and

bits<15:1> are SISR<15:1>.

Internal State The internal state at the time of the fault. The inter-

nal state has the following layout:

Delta-PC, bits<31:24> Difference between the values of the

current incremented PC at the time

that the machine check was de-

tected and the PC of the instruc-

tion opcode. The exact interpretation

of Delta-PC requires a detailed knowl-

edge of the internal pipeline opera-

tion of the MP-chip and is not used

by software to make recovery deci-

sions.

Unused, bits<23:21>

KA65A CPU Module Registers 4–37