add binary

twasm/asm/main.asm

@@ -730,7 +730,8 @@ tokenise:
 ; | type | p. | description  |
 ; |------|----|--------------|
 ; | 0x00 | 0x | hexidecimal  |
-; | 0x01 | 0b | octal        |
+; | 0x01 | 0q | octal        |
+; | 0x02 | 0b | binary       |
 ; | 0xFF |    | unrecognised |
 ;
 ; where `p.` is the prefix
@@ -774,6 +775,13 @@ evaluate_constant:
   je .oct_loop
   pop rcx
 
+  ; binary case
+  mov rcx, 0x02
+  push rcx
+  cmp dl, 'b'
+  je .bin_loop
+  pop rcx
+
   jmp .unrecognised
 
   .hex_loop:
@@ -822,6 +830,25 @@ evaluate_constant:
     inc rdi       ; point to next byte
     jmp .oct_loop ; and loop
 
+  .bin_loop:
+    cmp rsi, 0 ; range check
+    je .break
+
+    shl rax, 1
+
+    mov dl, [rdi]
+
+    sub dl, '0'
+    cmp dl, 1
+    jg .unrecognised
+
+    and dl, 1 ; mask
+    or al, dl ; and newest bit
+
+    dec rsi
+    inc rdi
+    jmp .bin_loop
+
   .break:
     pop rdx
     ret