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author | Andrew Waterman <andrew@sifive.com> | 2017-02-26 00:04:47 -0800 |
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committer | Andrew Waterman <andrew@sifive.com> | 2017-02-26 00:04:47 -0800 |
commit | 858664723437300176da81312471cee462dcecaf (patch) | |
tree | ce06cbd864e7dd543ed31f20f9c3671d9f9e6b4f /src | |
parent | 2659d3156c3e57da0091b2aacb706b4cd8f10172 (diff) | |
download | riscv-isa-manual-858664723437300176da81312471cee462dcecaf.zip riscv-isa-manual-858664723437300176da81312471cee462dcecaf.tar.gz riscv-isa-manual-858664723437300176da81312471cee462dcecaf.tar.bz2 |
SX -> SXL
Diffstat (limited to 'src')
-rw-r--r-- | src/machine.tex | 46 | ||||
-rw-r--r-- | src/supervisor.tex | 4 |
2 files changed, 25 insertions, 25 deletions
diff --git a/src/machine.tex b/src/machine.tex index f018af2..e469056 100644 --- a/src/machine.tex +++ b/src/machine.tex @@ -403,8 +403,8 @@ privilege-level ISAs respectively. \hline \multicolumn{1}{|c|}{SD} & \multicolumn{1}{c|}{\wpri} & -\multicolumn{1}{c|}{SX} & -\multicolumn{1}{c|}{UX} & +\multicolumn{1}{c|}{SXL} & +\multicolumn{1}{c|}{UXL} & \multicolumn{1}{c|}{\wpri} & \multicolumn{1}{c|}{TVM} & \multicolumn{1}{c|}{MXR} & @@ -527,39 +527,39 @@ embedded systems with only M-mode and U-mode present. \subsection{Base ISA Control in {\tt mstatus} Register} -The SX and UX fields control the value of XLEN for S-mode and U-mode, +The SXL and UXL fields control the value of XLEN for S-mode and U-mode, respectively. The encoding of these fields is the same as that of the Base field of {\tt misa}, shown in Table~\ref{misabase}. These fields only exist for RV64 and RV128; RV32 machines always use RV32 for S-mode and U-mode. -The SX field is only implemented if S-mode is implemented, and is otherwise -hard-wired to zero. An implementation may limit the values to which SX can be -set. The allowed values for SX may be a function of the machine XLEN. +The SXL field is only implemented if S-mode is implemented, and is otherwise +hard-wired to zero. An implementation may limit the values to which SXL can be +set. The allowed values for SXL may be a function of the machine XLEN. Changing the machine XLEN (such as by changing the Base field of {\tt misa}) -may cause SX to change as a side effect, regardless of whether the previous -value of SX would have been compatible with the new machine XLEN. An -implementation must enforce that SX specifies a width less than or equal to +may cause SXL to change as a side effect, regardless of whether the previous +value of SXL would have been compatible with the new machine XLEN. An +implementation must enforce that SXL specifies a width less than or equal to the machine XLEN. If the Base field of {\tt misa} is always nonzero, an -implementation may hard-wire SX to be a read-only copy of Base. +implementation may hard-wire SXL to be a read-only copy of Base. -The UX field is only implemented if U-mode is implemented, and is otherwise -hard-wired to zero. If S-mode is not supported, the allowed values for UX may +The UXL field is only implemented if U-mode is implemented, and is otherwise +hard-wired to zero. If S-mode is not supported, the allowed values for UXL may be a function of the machine XLEN. Changing the machine XLEN (such as by -changing the Base field of {\tt misa}) may cause UX to change as a side -effect, regardless of whether the previous value of UX would have been -compatible with the new machine XLEN. An implementation must enforce that UX +changing the Base field of {\tt misa}) may cause UXL to change as a side +effect, regardless of whether the previous value of UXL would have been +compatible with the new machine XLEN. An implementation must enforce that UXL specifies a width less than or equal to the machine XLEN. If the Base field of -{\tt misa} is always nonzero, an implementation may hard-wire UX to be a +{\tt misa} is always nonzero, an implementation may hard-wire UXL to be a read-only copy of Base. -If S-mode is supported, the allowed values for UX may be a function of the -value of field SX. Changing SX may cause UX to change as a side effect, -regardless of whether the previous value of UX would have been compatible with -the new SX. When an instruction explicitly writes both SX and UX together +If S-mode is supported, the allowed values for UXL may be a function of the +value of field SXL. Changing SXL may cause UXL to change as a side effect, +regardless of whether the previous value of UXL would have been compatible with +the new SXL. When an instruction explicitly writes both SXL and UXL together (such as a CSR instruction that writes {\tt mstatus}), the effect is as though -SX is written first, any side effects from changing SX occur, and then UX is -written. An implementation must enforce that UX is no greater than SX, and -may hard-wire UX to be a read-only copy of SX. +SXL is written first, any side effects from changing SXL occur, and then UXL is +written. An implementation must enforce that UXL is no greater than SXL, and +may hard-wire UXL to be a read-only copy of SXL. \subsection{Memory Privilege in {\tt mstatus} Register} diff --git a/src/supervisor.tex b/src/supervisor.tex index 74182cf..40a20ac 100644 --- a/src/supervisor.tex +++ b/src/supervisor.tex @@ -126,10 +126,10 @@ sstatus} is equivalent to reading or writing the homonymous field in \subsection{Base ISA Control in {\tt sstatus} Register} -The UX field controls the value of XLEN for U-mode. The encoding of UX is the +The UXL field controls the value of XLEN for U-mode. The encoding of UXL is the same as that of the Base field of {\tt misa}, shown in Table~\ref{misabase}. This field only exists for RV64 and RV128; RV32 machines always use RV32 for -U-mode. An implementation may limit the values to which UX can be set, but +U-mode. An implementation may limit the values to which UXL can be set, but U-mode XLEN must not exceed S-mode XLEN. \note{AW: add this to sstatus figure} |