aarch64: Add maximum immediate value to aarch64_sys_reg
The immediate form of MSR has a 4-bit immediate field (in CRm).
However, many forms of MSR require a smaller immediate. These cases
are identified by value in operand_general_constraint_met_p,
but they're now the common case rather than the exception.
This patch therefore adds the maximum value to the sys_reg
description and gets the range from there. It also enforces
the minimum of 0, which avoids a situation in which:
msr dit, #2
would give the expected:
Error: immediate value out of range 0 to 1
whereas:
msr dit, #-1
would give:
Error: immediate value out of range 0 to 15
(from the later UIMM4 checking).
Also:
- we were reporting the first error above against the wrong operand
- TCO takes a single-bit immediate, but we previously allowed
all 16 values.
[https://developer.arm.com/documentation/ddi0596/2021-09/Base-Instructions/MSR--immediate---Move-immediate-value-to-Special-Register-?lang=en]
opcodes/
* aarch64-opc.h (F_REG_MAX_VALUE, F_GET_REG_MAX_VALUE): New macros.
* aarch64-opc.c (operand_general_constraint_met_p): Read the
maximum MSR immediate value from aarch64_pstatefields.
(aarch64_pstatefields): Add the maximum immediate value
for each register.
gas/
* testsuite/gas/aarch64/sysreg-4.s: Use an immediate value of 1
rather than 8 for the TCO test.
* testsuite/gas/aarch64/sysreg-4.d: Update accordingly.
* testsuite/gas/aarch64/armv8_2-a-illegal.l: Fix operand number
in MSR immediate error messages.
* testsuite/gas/aarch64/diagnostic.l: Likewise.
* testsuite/gas/aarch64/pan-illegal.l: Likewise.
* testsuite/gas/aarch64/ssbs-illegal1.l: Likewise.
* testsuite/gas/aarch64/illegal-sysreg-4b.s,
* testsuite/gas/aarch64/illegal-sysreg-4b.d,
* testsuite/gas/aarch64/illegal-sysreg-4b.l: New test.
11 files changed
