From 7025f30be3b6cccf9f419daec9f0b7aeeaa2d6d3 Mon Sep 17 00:00:00 2001
From: Jacob McDonnell <jacob@jacobmcdonnell.com>
Date: Sun, 15 Mar 2026 20:59:54 -0400
Subject: refactor: Explicit register names & instructions

Explicit tokenization of register names and instructions. This forces
stricter syntax conformance and prevents errors from slipping through.
This also prevents the user from using these keywords as names other
than for their intended use.
---
 src/parser.y | 89 ++++++++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 59 insertions(+), 30 deletions(-)

(limited to 'src/parser.y')

diff --git a/src/parser.y b/src/parser.y
index 5f7b4bb..6998ddd 100644
--- a/src/parser.y
+++ b/src/parser.y
@@ -4,7 +4,7 @@
 #include <stdbool.h>
 #include <getopt.h>
 
-size_t line_number = 1;
+size_t line_number = 0;
 
 extern int yylex();
 extern int yyparse();
@@ -18,18 +18,22 @@ void yyerror(const char *s);
     char *symbol;
     char *modifier;
     char *directive;
+    char *reg;
+    char *instruction;
 }
 
-%token <i_val>     T_INTEGER
-%token <s_val>     T_STRING
-%token <symbol>    T_SYMBOL
-%token <directive> T_DIRECTIVE
-%token <symbol>    T_LABEL
-%token <modifier>  T_MODIFIER
-%token             T_ENDL
-%token             T_COMMA
-%token             T_OPENPAREN
-%token             T_CLOSEPAREN
+%token <i_val>       T_INTEGER
+%token <s_val>       T_STRING
+%token <symbol>      T_SYMBOL
+%token <directive>   T_DIRECTIVE
+%token <symbol>      T_LABEL
+%token <modifier>    T_MODIFIER
+%token <reg>         T_REGISTER
+%token <instruction> T_INSTRUCTION
+%token               T_ENDL
+%token               T_COMMA
+%token               T_OPENPAREN
+%token               T_CLOSEPAREN
 %%
 asm:
     statements
@@ -54,8 +58,9 @@ label:
     };
 
 instructions:
-    rb_type
-    | i_type
+    r_type
+    | ib_type_symbol
+    | i_type_integer
     | s_type
     | u_type
     | j_type
@@ -64,50 +69,74 @@ instructions:
     | pseudo_type
     ;
 
-rb_type:
-    T_SYMBOL T_SYMBOL T_COMMA T_SYMBOL T_COMMA T_SYMBOL T_ENDL
+r_type:
+    T_INSTRUCTION T_REGISTER T_COMMA T_REGISTER T_COMMA T_REGISTER T_ENDL
     {
-        printf("Read instruction: %s(%s, %s, %s)\n", $1, $2, $4, $6);
+        printf("Read R-Type instruction: %s(%s, %s, %s)\n", $1, $2, $4, $6);
     };
 
-i_type:
-    T_SYMBOL T_SYMBOL T_COMMA T_SYMBOL T_COMMA T_INTEGER T_ENDL
+ib_type_symbol:
+    T_INSTRUCTION T_REGISTER T_COMMA T_REGISTER T_COMMA T_SYMBOL T_ENDL
     {
-        printf("Read instruction: %s(%s, %s, %d)\n", $1, $2, $4, $6);
+        printf("Read I/B-Type instruction: %s(%s, %s, %s)\n", $1, $2, $4, $6);
+    };
+
+i_type_integer:
+    T_INSTRUCTION T_REGISTER T_COMMA T_REGISTER T_COMMA T_INTEGER T_ENDL
+    {
+        printf("Read I-Type instruction: %s(%s, %s, %d)\n", $1, $2, $4, $6);
     };
 
 i_type_modifier:
-    T_SYMBOL T_SYMBOL T_COMMA T_SYMBOL T_COMMA T_MODIFIER T_OPENPAREN T_SYMBOL T_CLOSEPAREN T_ENDL
+    T_INSTRUCTION T_REGISTER T_COMMA T_REGISTER T_COMMA T_MODIFIER T_OPENPAREN T_SYMBOL T_CLOSEPAREN T_ENDL
     {
-        printf("Read instruction: %s(%s, %s, %s of %s)\n", $1, $2, $4, $6, $8);
+        printf("Read I-Type instruction: %s(%s, %s, %s of %s)\n", $1, $2, $4, $6, $8);
     };
 
 s_type:
-    T_SYMBOL T_SYMBOL T_COMMA T_INTEGER T_OPENPAREN T_SYMBOL T_CLOSEPAREN T_ENDL
+    T_INSTRUCTION T_REGISTER T_COMMA T_INTEGER T_OPENPAREN T_REGISTER T_CLOSEPAREN T_ENDL
     {
-        printf("Read instruction: %s(%s, %s + %d)\n", $1, $2, $6, $4);
+        printf("Read S-Type instruction: %s(%s, %s + %d)\n", $1, $2, $6, $4);
     };
 
 s_type_modifier:
-    T_SYMBOL T_SYMBOL T_COMMA T_MODIFIER T_OPENPAREN T_SYMBOL T_CLOSEPAREN T_ENDL
+    T_INSTRUCTION T_REGISTER T_COMMA T_MODIFIER T_OPENPAREN T_SYMBOL T_CLOSEPAREN T_ENDL
     {
-        printf("Read instruction: %s(%s, %s of %s)\n", $1, $2, $4, $6);
+        printf("Read S-Type instruction: %s(%s, %s of %s)\n", $1, $2, $4, $6);
     };
 
 u_type:
-    T_SYMBOL T_SYMBOL T_COMMA T_INTEGER T_ENDL
+    T_INSTRUCTION T_REGISTER T_COMMA T_INTEGER T_ENDL
     {
-        printf("Read instruction: %s(%s, %d)\n", $1, $2, $4);
+        printf("Read U-Type instruction: %s(%s, %d)\n", $1, $2, $4);
     };
 
 j_type:
-    T_SYMBOL T_SYMBOL T_COMMA T_SYMBOL T_ENDL
+    T_INSTRUCTION T_REGISTER T_COMMA T_SYMBOL T_ENDL
     {
-        printf("Read instruction: %s(%s, %s)\n", $1, $2, $4);
+        printf("Read J-Type instruction: %s(%s, %s)\n", $1, $2, $4);
     };
 
 pseudo_type:
-    T_SYMBOL T_SYMBOL T_ENDL
+    pseudo_one_reg
+    | pseudo_two_reg
+    | pseudo_one_label
+    ;
+
+pseudo_one_reg:
+    T_INSTRUCTION T_REGISTER T_ENDL
+    {
+        printf("Read Pseudo Instruction: %s(%s)\n", $1, $2);
+    };
+
+pseudo_two_reg:
+    T_INSTRUCTION T_REGISTER T_COMMA T_REGISTER T_ENDL
+    {
+        printf("Read Pseudo Instruction: %s(%s, %s)\n", $1, $2, $4);
+    };
+
+pseudo_one_label:
+    T_INSTRUCTION T_SYMBOL T_ENDL
     {
         printf("Read Pseudo Instruction: %s(%s)\n", $1, $2);
     };
-- 
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