Implement x86 asm parsing support for %st and %st(4)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95634 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/AsmParser/X86AsmParser.cpp b/lib/Target/X86/AsmParser/X86AsmParser.cpp
index 10b00d5..acf497a 100644
--- a/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -292,6 +292,41 @@
// validation later, so maybe there is no need for this here.
RegNo = MatchRegisterName(Tok.getString());
+ // Parse %st(1) and "%st" as "%st(0)"
+ if (RegNo == 0 && Tok.getString() == "st") {
+ RegNo = X86::ST0;
+ EndLoc = Tok.getLoc();
+ Parser.Lex(); // Eat 'st'
+
+ // Check to see if we have '(4)' after %st.
+ if (getLexer().isNot(AsmToken::LParen))
+ return false;
+ // Lex the paren.
+ getParser().Lex();
+
+ const AsmToken &IntTok = Parser.getTok();
+ if (IntTok.isNot(AsmToken::Integer))
+ return Error(IntTok.getLoc(), "expected stack index");
+ switch (IntTok.getIntVal()) {
+ case 0: RegNo = X86::ST0; break;
+ case 1: RegNo = X86::ST1; break;
+ case 2: RegNo = X86::ST2; break;
+ case 3: RegNo = X86::ST3; break;
+ case 4: RegNo = X86::ST4; break;
+ case 5: RegNo = X86::ST5; break;
+ case 6: RegNo = X86::ST6; break;
+ case 7: RegNo = X86::ST7; break;
+ default: return Error(IntTok.getLoc(), "invalid stack index");
+ }
+
+ if (getParser().Lex().isNot(AsmToken::RParen))
+ return Error(Parser.getTok().getLoc(), "expected ')'");
+
+ EndLoc = Tok.getLoc();
+ Parser.Lex(); // Eat ')'
+ return false;
+ }
+
if (RegNo == 0)
return Error(Tok.getLoc(), "invalid register name");