oasm: Add initial support for labels

A label is like a pin on a map with a number attached to it. OASM keeps track
of a number referred to as the psuedo instruction pointer (PIP). This value is
initially zero by default and is incremented every instruction. The purpose of
this value is to pin a location in the code and mark it to be at a specific address
so that further references to that label would be translated to the previous PIP value
at the time of encountering the label.

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/usr.bin/oasm/parse.c b/usr.bin/oasm/parse.c
index 673fbcd..113671f 100644
--- a/usr.bin/oasm/parse.c
+++ b/usr.bin/oasm/parse.c
@@ -49,6 +49,8 @@ static const char *tokstr[] = {
     [ TT_DEC ] = "dec",
     [ TT_MOV ] = "mov",
     [ TT_IMM ]  = "<imm>",
+    [ TT_LABEL] = "<label>",
+
 
     /* X<n> registers */
     [ TT_X0 ]  = "x0",
@@ -150,6 +152,9 @@ parse_tok(struct oasm_state *state, struct oasm_token *tok)
         state->last = tok->type;
         emit_osmx64(&emit_state, tok);
         break;
+    case TT_LABEL:
+        state->last = tok->type;
+        break;
     case TT_HLT:
         state->last = tok->type;
         emit_osmx64(&emit_state, tok);