Hw_St Instruction; Hw_Ld Instruction Format; Hw_St Instruction Format; Opcodes Reserved For Palcode - Compaq 21264 Hardware Reference Manual

Opcodes Reserved for PALcode

Figure 6–1 HW_LD Instruction Format
31
TYPE
LEN
Table 6–3 describes the HW_LD instruction fields.
Table 6–3 HW_LD Instruction Fields Descriptions
Extent Mnemonic Value
[31:26] OPCODE 1B
[25:21] RA —
[20:16] RB —
[15:13] TYPE 000
001
010
100
101
110
111
[12] LEN 0
1
[11:0] DISP —

6.4.2 HW_ST Instruction

PALcode uses the HW_ST instruction to access memory outside the realm of normal
Alpha memory management and to do special forms of Dstream store instructions. Data
alignment traps are inhibited for HW_ST instructions. Figure 6–2 shows the HW_ST
instruction format.
Figure 6–2 HW_ST Instruction Format
31
TYPE
LEN
Privileged Architecture Library Code
6–4
26 25 21 20
OPCODE RA
Description
The opcode value.
16
Destination register number.
Base register for memory address.
Physical — The effective address for the HW_LD instruction is physical.
2
Physical/Lock — The effective address for the HW_LD instruction is
2
physical. It is the load lock version of the HW_LD instruction.
Virtual/VPTE — Flags a virtual PTE fetch (LD_VPTE). Used by trap logic
2
to distinguish a single TB miss from a double TB miss. Kernel mode access
checks are performed.
Virtual — The effective address for the HW_LD instruction is virtual.
2
Virtual/WrChk — The effective address for the HW_LD instruction is
2
virtual. Access checks for fault-on-read (FOR), fault-on-write (FOW), read
and write protection.
Virtual/Alt — The effective address for the HW_LD instruction is virtual.
2
Access checks use DTB_ALT_MODE IPR.
Virtual/WrChk/Alt — The effective address for the HW_LD instruction is
2
virtual. Access checks for FOR, FOW, read and write protection. Access
checks use DTB_ ALT_MODE IPR.
Access length is longword.
Access length is quadword.
Holds a 12-bit signed byte displacement.
26 25 21 20
OPCODE RA
16 15 13 12 11
RB
16 15 13 12 11
RB
Alpha 21264/EV67 Hardware Reference Manual
0
DISP
FM-05654.AI4
0
DISP
FM-05654.AI4