identify some tokens

twasm/asm/main.asm

@@ -912,6 +912,71 @@ evaluate_constant:
     mov rdx, 0xFF ; unrecognised type
     ret
 
+; ------------------------------------------------------------------------------
+; identify_register
+;
+; description:
+; takes a register in ascii-encoded text and returns its token ID or
+; UNRECOGNISED_TOKEN_ID if not recognised
+;
+; parameters:
+; edi = register to be searched
+;
+; returned:
+; ax = register's token ID or UNRECOGNISED_TOKEN_ID
+; ------------------------------------------------------------------------------
+
+identify_register:
+  xor eax, eax ; tokens.registers + eax -> entry in tokens.registers
+  .loop:
+    cmp eax, (tokens.registers_end - tokens.registers)
+    jge .not_found
+
+    cmp edi, [tokens.registers + eax]
+    je .found
+
+    add eax, 6
+    jmp .loop
+  .found:
+    mov ax, [tokens.registers + eax + 4]
+    ret
+  .not_found:
+    mov ax, UNRECOGNISED_TOKEN_ID
+    ret
+
+; ------------------------------------------------------------------------------
+; identify_operator
+; TODO combine with identify_register
+;
+; description:
+; takes an operator in ascii-encoded text and returns its token ID or
+; UNRECOGNISED_TOKEN_ID if not recognised
+;
+; parameters:
+; edi = operator to be searched
+;
+; returned:
+; ax = operator's token ID or UNRECOGNISED_TOKEN_ID
+; ------------------------------------------------------------------------------
+
+identify_operator:
+  xor eax, eax ; tokens.operators + eax -> entry in tokens.operators
+  .loop:
+    cmp eax, (tokens.operators_end - tokens.operators)
+    jge .not_found
+
+    cmp edi, [tokens.operators + eax]
+    je .found
+
+    add eax, 6
+    jmp .loop
+  .found:
+    mov ax, [tokens.operators + eax + 4]
+    ret
+  .not_found:
+    mov ax, UNRECOGNISED_TOKEN_ID
+    ret
+
 ; ------------------------------------------------------------------------------
 ; utilities
 ; ------------------------------------------------------------------------------