Harden RISC register parser and simplify expression evaluator.

[rmac] / riscasm.c

diff --git a/riscasm.c b/riscasm.c
index 4d62e97d7a0a11bfed64b1847a87cee659931623..5681f354e5a1d480d7a97783a9f9f138e663d058 100644 (file)
--- a/riscasm.c
+++ b/riscasm.c
@@ -25,6 +25,22 @@
 
 #define MAXINTERNCC 26         // Maximum internal condition codes
 
+// Useful macros
+#define EVAL_REG_RETURN_IF_ERROR(x, y) \
+x = EvaluateRegisterFromTokenStream(y); \
+\
+if (x == ERROR) \
+       return ERROR;
+
+#define EVAL_REG_RETURN_IF_ERROR_OR_NO_EOL(x, y) \
+x = EvaluateRegisterFromTokenStream(y); \
+\
+if ((x == ERROR) || (ErrorIfNotAtEOL() == ERROR)) \
+       return ERROR;
+
+#define CHECK_EOL \
+if (ErrorIfNotAtEOL() == ERROR) \
+       return ERROR;
 
 unsigned altbankok = 0;                // Ok to use alternate register bank
 unsigned orgactive = 0;                // RISC/6502 org directive active
@@ -134,7 +150,6 @@ static const char * malformErr[] = {
        malform1, malform2, malform3, malform4
 };
 
-
 //
 // Function to return "malformed expression" error
 // This is done mainly to remove a bunch of GOTO statements in the parser
@@ -144,7 +159,6 @@ static inline int MalformedOpcode(int signal)
        return error("Malformed opcode, %s", malformErr[signal]);
 }
 
-
 //
 // Function to return "Illegal Indexed Register" error
 // Anyone trying to index something other than R14 or R15
@@ -154,7 +168,6 @@ static inline int IllegalIndexedRegister(int reg)
        return error("Attempted index reference with non-indexable register (r%d)", reg - KW_R0);
 }
 
-
 //
 // Function to return "Illegal Indexed Register" error for EQUR scenarios
 // Trying to use register value within EQUR that isn't 14 or 15
@@ -164,7 +177,6 @@ static inline int IllegalIndexedRegisterEqur(SYM * sy)
        return error("Attempted index reference with non-indexable register within EQUR (%s = r%d)", sy->sname, sy->svalue);
 }
 
-
 //
 // Build up & deposit RISC instruction word
 //
@@ -181,25 +193,40 @@ static void DepositRISCInstructionWord(uint16_t opcode, int reg1, int reg2)
        D_word(value);
 }
 
-
 //
 // Evaluate the RISC register from the token stream. Passed in value is the
 // FIXUP attribute to use if the expression comes back as undefined.
 //
-static int EvaluateRegisterFromTokenStream(uint32_t attr)
+static int EvaluateRegisterFromTokenStream(uint32_t fixup)
 {
+       // Firstly, check to see if it's a register token and return that.  No
+       // need to invoke expr() for easy cases like this.
+       if (*tok >= KW_R0 && *tok <= KW_R31)
+       {
+               int reg = *tok - KW_R0;
+               tok++;
+               return reg;
+       }
+
+       if (*tok != SYMBOL)
+       {
+               // If at this point we don't have a symbol then it's garbage.  Punt.
+               return error("Expected register number or EQUREG");
+       }
+
        uint64_t eval;                          // Expression value
        WORD eattr;                                     // Expression attributes
        SYM * esym;                                     // External symbol involved in expr.
        TOKEN r_expr[EXPRSIZE];         // Expression token list
 
        // Evaluate what's in the global "tok" buffer
+       // N.B.: We should either get a fixup or a register name from EQUR
        if (expr(r_expr, &eval, &eattr, &esym) != OK)
                return ERROR;
 
        if (!(eattr & DEFINED))
        {
-               AddFixup(FU_WORD | attr, sloc, r_expr);
+               AddFixup(FU_WORD | fixup, sloc, r_expr);
                return 0;
        }
 
@@ -211,7 +238,6 @@ static int EvaluateRegisterFromTokenStream(uint32_t attr)
        return error(reg_err);
 }
 
-
 //
 // Do RISC code generation
 //
@@ -257,8 +283,7 @@ int GenerateRISCCode(int state)
        // ABS, MIRROR, NEG, NOT, PACK, RESMAC, SAT8, SAT16, SAT16S, SAT24, SAT32S,
        // UNPACK
        case RI_ONE:
-               reg2 = EvaluateRegisterFromTokenStream(FU_REGTWO);
-               ErrorIfNotAtEOL();
+               EVAL_REG_RETURN_IF_ERROR_OR_NO_EOL(reg2, FU_REGTWO);
                DepositRISCInstructionWord(parm, parm >> 6, reg2);
                break;
 
@@ -269,14 +294,13 @@ int GenerateRISCCode(int state)
                if (parm == 37)
                        altbankok = 1;                      // MOVEFA
 
-               reg1 = EvaluateRegisterFromTokenStream(FU_REGONE);
+               EVAL_REG_RETURN_IF_ERROR(reg1, FU_REGONE);
                CHECK_COMMA;
 
                if (parm == 36)
                        altbankok = 1;                      // MOVETA
 
-               reg2 = EvaluateRegisterFromTokenStream(FU_REGTWO);
-               ErrorIfNotAtEOL();
+               EVAL_REG_RETURN_IF_ERROR_OR_NO_EOL(reg2, FU_REGTWO);
                DepositRISCInstructionWord(parm, reg1, reg2);
                break;
 
@@ -343,8 +367,7 @@ int GenerateRISCCode(int state)
                }
 
                CHECK_COMMA;
-               reg2 = EvaluateRegisterFromTokenStream(FU_REGTWO);
-               ErrorIfNotAtEOL();
+               EVAL_REG_RETURN_IF_ERROR_OR_NO_EOL(reg2, FU_REGTWO);
                DepositRISCInstructionWord(parm, reg1, reg2);
                break;
 
@@ -392,8 +415,7 @@ int GenerateRISCCode(int state)
                }
 
                CHECK_COMMA;
-               reg2 = EvaluateRegisterFromTokenStream(FU_REGTWO);
-               ErrorIfNotAtEOL();
+               EVAL_REG_RETURN_IF_ERROR_OR_NO_EOL(reg2, FU_REGTWO);
 
                DepositRISCInstructionWord(parm, 0, reg2);
                val = WORDSWAP32(eval);
@@ -411,12 +433,11 @@ int GenerateRISCCode(int state)
                else
                {
                        parm = 34;
-                       reg1 = EvaluateRegisterFromTokenStream(FU_REGONE);
+                       EVAL_REG_RETURN_IF_ERROR(reg1, FU_REGONE);
                }
 
                CHECK_COMMA;
-               reg2 = EvaluateRegisterFromTokenStream(FU_REGTWO);
-               ErrorIfNotAtEOL();
+               EVAL_REG_RETURN_IF_ERROR_OR_NO_EOL(reg2, FU_REGTWO);
                DepositRISCInstructionWord(parm, reg1, reg2);
                break;
 
@@ -465,7 +486,7 @@ int GenerateRISCCode(int state)
 
                if (!indexed)
                {
-                       reg1 = EvaluateRegisterFromTokenStream(FU_REGONE);
+                       EVAL_REG_RETURN_IF_ERROR(reg1, FU_REGONE);
                }
                else
                {
@@ -497,7 +518,7 @@ int GenerateRISCCode(int state)
 
                                if (indexed)
                                {
-                                       reg1 = EvaluateRegisterFromTokenStream(FU_REGONE);
+                                       EVAL_REG_RETURN_IF_ERROR(reg1, FU_REGONE);
                                }
                                else
                                {
@@ -529,7 +550,7 @@ int GenerateRISCCode(int state)
                        }
                        else
                        {
-                               reg1 = EvaluateRegisterFromTokenStream(FU_REGONE);
+                               EVAL_REG_RETURN_IF_ERROR(reg1, FU_REGONE);
                        }
                }
 
@@ -538,15 +559,14 @@ int GenerateRISCCode(int state)
 
                tok++;
                CHECK_COMMA;
-               reg2 = EvaluateRegisterFromTokenStream(FU_REGTWO);
-               ErrorIfNotAtEOL();
+               EVAL_REG_RETURN_IF_ERROR_OR_NO_EOL(reg2, FU_REGTWO);
                DepositRISCInstructionWord(parm, reg1, reg2);
                break;
 
        // Rn,(Rn) = 47 / Rn,(R14/R15+n) = 49/50 / Rn,(R14/R15+Rn) = 60/61
        case RI_STORE:
                parm = 47;
-               reg1 = EvaluateRegisterFromTokenStream(FU_REGONE);
+               EVAL_REG_RETURN_IF_ERROR(reg1, FU_REGONE);
                CHECK_COMMA;
 
                if (*tok != '(')
@@ -581,7 +601,7 @@ int GenerateRISCCode(int state)
 
                if (!indexed)
                {
-                       reg2 = EvaluateRegisterFromTokenStream(FU_REGTWO);
+                       EVAL_REG_RETURN_IF_ERROR(reg2, FU_REGTWO);
                }
                else
                {
@@ -613,7 +633,7 @@ int GenerateRISCCode(int state)
 
                                if (indexed)
                                {
-                                       reg2 = EvaluateRegisterFromTokenStream(FU_REGTWO);
+                                       EVAL_REG_RETURN_IF_ERROR(reg2, FU_REGTWO);
                                }
                                else
                                {
@@ -650,7 +670,7 @@ int GenerateRISCCode(int state)
                        }
                        else
                        {
-                               reg2 = EvaluateRegisterFromTokenStream(FU_REGTWO);
+                               EVAL_REG_RETURN_IF_ERROR(reg2, FU_REGTWO);
                        }
                }
 
@@ -658,7 +678,7 @@ int GenerateRISCCode(int state)
                        return MalformedOpcode(MALF_RPAREN);
 
                tok++;
-               ErrorIfNotAtEOL();
+               CHECK_EOL;
                DepositRISCInstructionWord(parm, reg2, reg1);
                break;
 
@@ -668,34 +688,33 @@ int GenerateRISCCode(int state)
                        return MalformedOpcode(MALF_LPAREN);
 
                tok++;
-               reg1 = EvaluateRegisterFromTokenStream(FU_REGONE);
+               EVAL_REG_RETURN_IF_ERROR(reg1, FU_REGONE);
 
                if (*tok != ')')
                        return MalformedOpcode(MALF_RPAREN);
 
                tok++;
                CHECK_COMMA;
-               reg2 = EvaluateRegisterFromTokenStream(FU_REGTWO);
-               ErrorIfNotAtEOL();
+               EVAL_REG_RETURN_IF_ERROR_OR_NO_EOL(reg2, FU_REGTWO);
                DepositRISCInstructionWord(parm, reg1, reg2);
                break;
 
        // STOREB/STOREP/STOREW Rn,(Rn)
        case RI_STOREN:
-               reg1 = EvaluateRegisterFromTokenStream(FU_REGONE);
+               EVAL_REG_RETURN_IF_ERROR(reg1, FU_REGONE);
                CHECK_COMMA;
 
                if (*tok != '(')
                        return MalformedOpcode(MALF_LPAREN);
 
                tok++;
-               reg2 = EvaluateRegisterFromTokenStream(FU_REGTWO);
+               EVAL_REG_RETURN_IF_ERROR(reg2, FU_REGTWO);
 
                if (*tok != ')')
                        return MalformedOpcode(MALF_RPAREN);
 
                tok++;
-               ErrorIfNotAtEOL();
+               CHECK_EOL;
                DepositRISCInstructionWord(parm, reg2, reg1);
                break;
 
@@ -802,13 +821,13 @@ int GenerateRISCCode(int state)
                                return MalformedOpcode(MALF_LPAREN);
 
                        tok++;
-                       reg2 = EvaluateRegisterFromTokenStream(FU_REGTWO);
+                       EVAL_REG_RETURN_IF_ERROR(reg2, FU_REGTWO);
 
                        if (*tok != ')')
                                return MalformedOpcode(MALF_RPAREN);
 
                        tok++;
-                       ErrorIfNotAtEOL();
+                       CHECK_EOL;
                }
 
                DepositRISCInstructionWord(parm, reg2, reg1);
@@ -822,4 +841,3 @@ int GenerateRISCCode(int state)
        lastOpcode = type;
        return 0;
 }
-