CP0.PageGrain.ELPA enables support for large physical addresses. This field
is encoded as follows:
0: Large physical address support is disabled.
1: Large physical address support is enabled.
If this bit is a 1, the following changes occur to coprocessor 0 registers:
- The PFNX field of the EntryLo0 and EntryLo1 registers is writable and
concatenated with the PFN field to form the full page frame number.
- Access to optional COP0 registers with PA extension, LLAddr, TagLo is
defined.
P5600 can operate in 32-bit or 40-bit Physical Address Mode. Therefore if
XPA is disabled (CP0.PageGrain.ELPA = 0) then assume 32-bit Address Mode.
In MIPS64 assume 36 as default PABITS (when CP0.PageGrain.ELPA = 0).
env->PABITS value is constant and indicates maximum PABITS available on
a core, whereas env->PAMask is calculated from env->PABITS and is also
affected by CP0.PageGrain.ELPA.
Backports commit e117f52636d04502fab28bd3abe93347c29f39a5 from qemu
Extend EntryLo0, EntryLo1, LLAddr and TagLo from 32 to 64 bits in MIPS32.
Introduce gen_move_low32() function which moves low 32 bits from 64-bit
temp to GPR; it sign extends 32-bit value on MIPS64 and truncates on
MIPS32.
Backports commit 284b731a6ae47b9ebabb9613e753c4d83cf75dd3 from qemu
ERETNC is identical to ERET except that an ERETNC will not clear the LLbit
that is set by execution of an LL instruction, and thus when placed between
an LL and SC sequence, will never cause the SC to fail.
Presence of ERETNC is denoted by the Config5.LLB.
Backports commit ce9782f40ac16660ea9437bfaa2c9c34d5ed8110 from qemu
This relatively small architectural feature adds the following:
FIR.FREP: Read-only. If FREP=1, then Config5.FRE and Config5.UFE are
available.
Config5.FRE: When enabled all single-precision FP arithmetic instructions,
LWC1/LWXC1/MTC1, SWC1/SWXC1/MFC1 cause a Reserved Instructions
exception.
Config5.UFE: Allows user to write/read Config5.FRE using CTC1/CFC1
instructions.
Enable the feature in MIPS64R6-generic CPU.
Backports commit 7c979afd11b09a16634699dd6344e3ba10c9677e from qemu
Save MSACSR state. Also remove fp_status, msa_fp_status, hflags and restore
them in post_load() from the architectural registers.
Float exception flags are not present in vmstate. Information they carry
is used only by softfloat caller who translates them into MIPS FCSR.Cause,
FCSR.Flags and then they are cleared. Therefore there is no need for saving
them in vmstate.
Backports commit 644511117e7ca9f26d633a59c202a297113a796c from qemu
Add missing calls to synchronise the SoftFloat status with the CP1.FSCR:
+ for the rounding and flush-to-zero modes upon processor reset,
+ for the flush-to-zero mode on FSCR updates through the GDB stub.
Refactor code accordingly and remove the redundant RESTORE_ROUNDING_MODE
macro.
Backports commit bb962386b82c1b0e9e12fdb6b9bb62106bf1f822 from qemu
Make sure the address space is unconditionally wrapped on 32-bit
processors, that is ones that do not implement at least the MIPS III
ISA.
Also make MIPS16 SAVE and RESTORE instructions use address calculation
rather than plain arithmetic operations for stack pointer manipulation
so that their semantics for stack accesses follows the architecture
specification. That in particular applies to user software run on
64-bit processors with the CP0.Status.UX bit clear where the address
space is wrapped to 32 bits.
Backports commit c48245f0c62405f27266fcf08722d8c290520418 from qemu
Tighten ISA level checks down to MIPS II that many of our instructions
are missing. Also make sure any 64-bit instruction enables are only
applied to 64-bit processors, that is ones that implement at least the
MIPS III ISA.
Backports commit d9224450208e0de62323b64ace91f98bc31d6e2c from qemu
Make writes to CP0.Status and CP0.Cause have the same effect as
executing corresponding MTC0 instructions would in Kernel Mode. Also
ignore writes in the user emulation mode.
Currently for requests from the GDB stub we write all the bits across
both registers, ignoring any read-only locations, and do not synchronise
the environment to evaluate side effects. We also write these registers
in the user emulation mode even though a real kernel presents them as
read only.
Backports commit 81a423e6c6d3ccaa79de4e58024369c660c1eeb4 from qemu
Make the data type used for the CP0.Config4 and CP0.Config5 registers
and their mask signed, for consistency with the remaining 32-bit CP0
registers, like CP0.Config0, etc.
Backports commit 8280b12c0e4b515d707509dde4ddde05d9bda4ef from qemu
