Clarify which hints are C.NOP hints and which are C.ADDI hints

Closes #389

1 files changed, 5 insertions, 4 deletions

diff --git a/src/c.tex b/src/c.tex
index 7a2a8fe..533fb8b 100644
--- a/src/c.tex
+++ b/src/c.tex
@@ -815,9 +815,9 @@ C.ADDI16SP & nzimm[9] & 2 & nzimm[4$\vert$6$\vert$8:7$\vert$5] & C1 \\
 C.ADDI adds the non-zero sign-extended 6-bit immediate to the value in
 register {\em rd} then writes the result to {\em rd}.  C.ADDI expands
 into {\tt addi rd, rd, nzimm[5:0]}.
-C.ADDI is only valid when {\em rd}$\neq${\tt x0}.
-The code point with both {\em rd}={\tt x0} and {\em nzimm}=0 encodes the C.NOP instruction;
-the remaining code points with either {\em rd}={\tt x0} or {\em nzimm}=0 encode HINTs.
+C.ADDI is only valid when {\em rd}$\neq${\tt x0} and {\em nzimm}$\neq$0.
+The code points with {\em rd}={\tt x0} encode the C.NOP instruction;
+the remaining code points with {\em nzimm}=0 encode HINTs.
 
 C.ADDIW is an RV64C/RV128C-only instruction that performs the same
 computation but produces a 32-bit result, then sign-extends result to
@@ -1145,7 +1145,8 @@ C.NOP & 0 & 0 & 0 & C1 \\
 
 C.NOP is a CI-format instruction that does not change any user-visible state,
 except for advancing the {\tt pc} and incrementing any applicable performance
-counters.  C.NOP expands to {\tt nop}.
+counters.  C.NOP expands to {\tt nop}.  C.NOP is only valid when {\em imm}=0;
+the code points with {\em imm}$\neq$0 encode HINTs.
 
 \subsection*{Breakpoint Instruction}
 \vspace{-0.4in}