Certain ARM instructions accept 32-bit immediate operands encoded as a 8-bit
integer value (0-255) and a 4-bit rotation (0-30, even). Current ARM assembly
syntax support in LLVM allows the decoded (32-bit) immediate to be specified
as a single immediate operand for such instructions:
mov r0, #4278190080
The ARMARM defines an extended assembly syntax allowing the encoding to be made
more explicit, as in:
mov r0, #255, #8 ; (same 32-bit value as above)
The behaviour of the two instructions can be different w.r.t flags, which is
documented under "Modified immediate constants" in ARMARM. This patch enables
support for this extended syntax at the MC layer.
llvm-svn: 223113
This CPU definition is redundant. The Cortex-A9 is defined as
supporting multiprocessing extensions. Remove its definition and
update appropriate tests.
LLVM defines both a cortex-a9 CPU and a cortex-a9-mp CPU. The only
difference between the two CPU definitions in ARM.td is that
cortex-a9-mp contains the feature FeatureMP for multiprocessing
extensions.
This is redundant since the Cortex-A9 is defined as having
multiprocessing extensions in the TRMs. armcc also defines the
Cortex-A9 as having multiprocessing extensions by default.
Change-Id: Ifcadaa6c322be0a33d9d2a39cfdd7da1d75981a7
llvm-svn: 221166
The cdp2 instruction should have the same restrictions as cdp on the
co-processor registers.
VFP instructions on v8/AArch32 share the same encoding space as cdp2.
llvm-svn: 184445
According to the ARM reference manual, constant offsets are mandatory for pre-indexed addressing modes.
The MC disassembler was not obeying this when the offset is 0.
It was producing instructions like: str r0, [r1]!.
Correct syntax is: str r0, [r1, #0]!.
This change modifies the dumping of operands so that the offset is always printed, regardless of its value, when pre-indexed addressing mode is used.
Patch by Mihail Popa <Mihail.Popa@arm.com>
llvm-svn: 179398
This new disassembler can correctly decode all the testcases that the old one did, though
some "expected failure" testcases are XFAIL'd for now because it is not (yet) as strict in
operand checking as the old one was.
llvm-svn: 137144
Memory operand parsing is a bit haphazzard at the moment, in no small part
due to the even more haphazzard representations of memory operands in the .td
files. Start cleaning that all up, at least a bit.
The addressing modes in the .td files will be being simplified to not be
so monolithic, especially with regards to immediate vs. register offsets
and post-indexed addressing. addrmode3 is on its way with this patch, for
example.
This patch is foundational to enable going back to smaller incremental patches
for the individual memory referencing instructions themselves. It does just
enough to get the basics in place and handle the "make check" regression tests
we already have.
Follow-up work will be fleshing out the details and adding more robust test
cases for the individual instructions, starting with ARM mode and moving from
there into Thumb and Thumb2.
llvm-svn: 136845
Fix the instruction encoding for operands. Refactor mode to use explicit
instruction definitions per FIXME to be more consistent with loads/stores.
Fix disassembler accordingly. Add tests.
llvm-svn: 136509
The system register spec should be case insensitive. The preferred form for
output with mask values of 4, 8, and 12 references APSR rather than CPSR.
Update and tidy up tests accordingly.
llvm-svn: 135532
Print shifted immediate values directly rather than as a payload+shifter
value pair. This makes for more readable output assembly code, simplifies
the instruction printer, and is consistent with how Thumb immediates are
displayed.
llvm-svn: 134902
Add more complete sanity check for LdStFrm instructions where if IBit (Inst{25})
is 1, Inst{4} should be 0. Otherwise, we should reject the insn as invalid.
rdar://problem/9239347
rdar://problem/9239467
llvm-svn: 128977
An alternative syntax is available for a modified immediate constant that permits the programmer to specify
the encoding directly. In this syntax, #<const> is instead written as #<byte>,#<rot>, where:
<byte> is the numeric value of abcdefgh, in the range 0-255
<rot> is twice the numeric value of rotation, an even number in the range 0-30.
llvm-svn: 128897
Set the encoding bits to {0,?,?,0}, not 0. Plus delegate the disassembly of ADR to
the more generic ADDri/SUBri instructions, and add a test case for that.
llvm-svn: 128234
These instructions were changed to not embed the addressing mode within the MC instructions
We also need to update the corresponding assert stmt. Also add two test cases.
llvm-svn: 128191
Asiri Rathnayake