- Refactored the opcode table, in order to make the

  instruction formatting simpler.

- Refactored the instruction table of the emulator's
  assembler, it now has two parts, the addressing mode
  bits, and the base value.

  The base value is what's used to generate the actual
  opcode, with the addressing mode bits telling the
  assembler what addressing modes this instruction
  supports.

  The reason for doing this was to use less space. For
  comparison, the previous version used 870 bytes for
  the instruction table, while the new version uses
  only 222 bytes. The new version is nearly 4 times
  smaller than the pervious version.

- The B register based ALU instructions now use their
  own addressing mode, and are specified by using 'b'
  as the operand for those instructions.
  For example, to add the Accumulator with the B
  register, you now use "ADC B" instead of "AAB".

1 files changed, 12 insertions, 0 deletions

diff --git a/lexer.h b/lexer.h
index 952d525..225a5e5 100644
--- a/lexer.h
+++ b/lexer.h
@@ -44,6 +44,7 @@ static inline uint8_t get_ptok(char c, uint8_t dbg) {
 		  case '(' : return PTOK_LBRACK ;
 		  case ')' : return PTOK_RBRACK ;
 		  case ',' : return PTOK_COMMA  ;
+	case 'B': case 'b' : return PTOK_B      ;
 	case 'X': case 'x' : return PTOK_X	;
 	case 'Y': case 'y' : return PTOK_Y	;
 	case 'S': case 's' : return PTOK_S	;
@@ -64,3 +65,14 @@ static inline uint8_t get_ptok(char c, uint8_t dbg) {
 			}
 	}
 }
+
+static inline uint8_t is_altok(uint8_t ptok, uint8_t dbg) {
+	switch (ptok) {
+		case PTOK_B:
+		case PTOK_X:
+		case PTOK_Y:
+		case PTOK_S:
+		case PTOK_P: return 1;
+		default    : return 0;
+	}
+}