Clarify effect on unwritten bits for CSRRS/CSRRC

They aren't _explicitly_ written, but that doesn't mean they are
unaffected, since they could change as a result of the bits that
are written.

Resolves #549

1 files changed, 3 insertions, 4 deletions

diff --git a/src/csr.tex b/src/csr.tex
index b1b7336..a72553c 100644
--- a/src/csr.tex
+++ b/src/csr.tex
@@ -63,16 +63,15 @@ to integer register {\em rd}.  The initial value in integer register
 {\em rs1} is treated as a bit mask that specifies bit positions to be
 set in the CSR.  Any bit that is high in {\em rs1} will cause the
 corresponding bit to be set in the CSR, if that CSR bit is writable.
-Other bits in the CSR are unaffected (though CSRs might have side
-effects when written).
+Other bits in the CSR are not explicitly written.
 
 The CSRRC (Atomic Read and Clear Bits in CSR) instruction reads the
 value of the CSR, zero-extends the value to XLEN bits, and writes it
 to integer register {\em rd}.  The initial value in integer register
 {\em rs1} is treated as a bit mask that specifies bit positions to be
 cleared in the CSR.  Any bit that is high in {\em rs1} will cause the
-corresponding bit to be cleared in the CSR, if that CSR bit is
-writable.  Other bits in the CSR are unaffected.
+corresponding bit to be cleared in the CSR, if that CSR bit is writable.
+Other bits in the CSR are not explicitly written.
 
 For both CSRRS and CSRRC, if {\em rs1}={\tt x0}, then the instruction
 will not write to the CSR at all, and so shall not cause any of the