Pal Base Register - Pal_Base; Ibox Control Register - I_Ctl; Pal Base Register; Pal Base Register Fields Description - Compaq 21264 Hardware Reference Manual

Table 5–9 Exception Summary Register Fields Description (Continued)
Name
REG[4:0]
INT
IOV
INE
UNF
FOV
DZE
INV
SWC
5.2.14 PAL Base Register – PAL_BASE
The PAL base register (PAL_BASE) is a read-write register that contains the base phys-
ical address for PALcode. Its contents are cleared by chip reset but are not cleared after
waking up from sleep mode or from fault reset. Figure 5–21 shows the PAL base regis-
ter.
Figure 5–21 PAL Base Register
63
PAL_BASE[43:15]
Table 5–10 describes the PAL base register fields.
Table 5–10 PAL Base Register Fields Description
Name
Reserved
PAL_BASE[43:15]
Reserved
5.2.15 Ibox Control Register – I_CTL
The Ibox control register (I_CTL) is a read-write register that controls various Ibox
functions. Its contents are cleared by chip reset. Figure 5–22 shows the Ibox control
register.
Alpha 21264/EV67 Hardware Reference Manual
Extent Type Description
[12:8] RO Destination register of load or operate instruction that triggered
the trap OR source register of store that triggered the trap. These
bits may contain the Rc field of an operate instruction or the Ra
field of a load or store instruction. The value is UNPREDICTABLE
if the trap was triggered by an ITB miss, interrupt, OPCDEC, or
other non load/st/operate.
[7] RO Set to indicate Ebox integer overflow trap, clear to indicate Fbox
trap condition.
[6] RO Indicates Fbox convert-to-integer overflow or Ebox integer over-
flow trap.
[5] RO Indicates floating-point inexact error trap.
[4] RO Indicates floating-point underflow trap.
[3] RO Indicates floating-point overflow trap.
[2] RO Indicates divide by zero trap.
[1] RO Indicates invalid operation trap.
[0] RO Indicates software completion possible. This bit is set if the
instruction that triggered the trap contained the /S modifier.
44 43
Extent Type Description
[63:44] RO, 0 Reserved for Compaq.
[43:15] RW Base physical address for PALcode.
[14:0] RO, 0 Reserved for Compaq.
Ibox IPRs
15 14
Internal Processor Registers
0
LK99-0027A
5–15