From caa652ae2b3da86de945fa8d5ece55ddbbb2cf31 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Wed, 30 Jul 2025 16:34:48 -0400
Subject: oasm: Introduce logical shift operations

This commit introduces LSR/LSL which are used as bitwise shift
operations.

--
lsr x1, #1   !! x1 >>= 1
lsl x1, #1   !! x1 <<= 1
--

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 usr.bin/oasm/emit.c              | 10 ++++++++++
 usr.bin/oasm/include/oasm/emit.h |  2 ++
 usr.bin/oasm/include/oasm/lex.h  |  2 ++
 usr.bin/oasm/lex.c               |  8 ++++++++
 usr.bin/oasm/parse.c             | 14 +++++++++++++-
 5 files changed, 35 insertions(+), 1 deletion(-)

(limited to 'usr.bin')

diff --git a/usr.bin/oasm/emit.c b/usr.bin/oasm/emit.c
index 63f716a..099f0b2 100644
--- a/usr.bin/oasm/emit.c
+++ b/usr.bin/oasm/emit.c
@@ -402,6 +402,14 @@ emit_encode_bitw(struct emit_state *state, struct oasm_token *tok)
         opcode = OSMX64_XOR;
         inst_str = "xor";
         break;
+    case TT_LSR:
+        opcode = OSMX64_LSR;
+        inst_str = "lsr";
+        break;
+    case TT_LSL:
+        opcode = OSMX64_LSL;
+        inst_str = "lsl";
+        break;
     }
 
     /* Next token should be a register */
@@ -532,6 +540,8 @@ emit_process(struct oasm_state *oasm, struct emit_state *emit)
         case TT_AND:
         case TT_OR:
         case TT_XOR:
+        case TT_LSR:
+        case TT_LSL:
             curtok = emit_encode_bitw(emit, curtok);
             break;
         case TT_BR:
diff --git a/usr.bin/oasm/include/oasm/emit.h b/usr.bin/oasm/include/oasm/emit.h
index 3fc2674..57683a8 100644
--- a/usr.bin/oasm/include/oasm/emit.h
+++ b/usr.bin/oasm/include/oasm/emit.h
@@ -66,6 +66,8 @@
 #define OSMX64_MROW     0x11    /* Mask register over word */
 #define OSMX64_MROD     0x12    /* Mask register over dword */
 #define OSMX64_MROQ     0x13    /* Mask register over qword */
+#define OSMX64_LSR      0x14    /* Logical shift right */
+#define OSMX64_LSL      0x15    /* Logical shift left */
 
 /*
  * OSMX64 register definitions
diff --git a/usr.bin/oasm/include/oasm/lex.h b/usr.bin/oasm/include/oasm/lex.h
index 4c81bc4..93422a6 100644
--- a/usr.bin/oasm/include/oasm/lex.h
+++ b/usr.bin/oasm/include/oasm/lex.h
@@ -106,6 +106,8 @@ typedef enum {
     TT_AND,         /* 'and' */
     TT_OR,          /* 'or' */
     TT_XOR,         /* 'xor' */
+    TT_LSR,         /* 'lsr' */
+    TT_LSL,         /* 'lsl' */
 
     /* Register ops */
     TT_MOV,         /* 'mov' */
diff --git a/usr.bin/oasm/lex.c b/usr.bin/oasm/lex.c
index ce97400..1f58d07 100644
--- a/usr.bin/oasm/lex.c
+++ b/usr.bin/oasm/lex.c
@@ -57,6 +57,8 @@ static char putback = '\0';
 #define S_IMN_AND  "and"
 #define S_IMN_OR   "or"
 #define S_IMN_XOR  "xor"
+#define S_IMN_LSL  "lsl"
+#define S_IMN_LSR  "lsr"
 
 /* Instruction length */
 #define OSMX64_INST_LEN 4
@@ -269,6 +271,12 @@ token_bitw(char *p)
         return token;
     }
 
+    if (strcmp(p, S_IMN_LSL) == 0) {
+        return TT_LSL;
+    } else if (strcmp(p, S_IMN_LSR) == 0) {
+        return TT_LSR;
+    }
+
     return TT_UNKNOWN;
 }
 
diff --git a/usr.bin/oasm/parse.c b/usr.bin/oasm/parse.c
index ce5a446..042cce8 100644
--- a/usr.bin/oasm/parse.c
+++ b/usr.bin/oasm/parse.c
@@ -51,7 +51,9 @@ static const char *tokstr[] = {
     [ TT_DEC ] = "dec",
     [ TT_MOV ] = "mov",
     [ TT_IMM ]  = "<imm>",
-    [ TT_LABEL] = "<label>",
+    [ TT_LABEL ] = "<label>",
+    [ TT_LSR ] = "lsr",
+    [ TT_LSL ] = "lsl",
 
     /* Bitwise */
     [ TT_MROB ] = "mrob",
@@ -129,6 +131,8 @@ parse_reg(struct oasm_state *state, struct oasm_token *tok)
     case TT_AND:
     case TT_OR:
     case TT_XOR:
+    case TT_LSR:
+    case TT_LSL:
         state->last = tok->type;
         break;
     default:
@@ -195,6 +199,14 @@ parse_tok(struct oasm_state *state, struct oasm_token *tok)
         state->last = tok->type;
         emit_osmx64(&emit_state, tok);
         break;
+    case TT_LSR:
+        state->last = tok->type;
+        emit_osmx64(&emit_state, tok);
+        break;
+    case TT_LSL:
+        state->last = tok->type;
+        emit_osmx64(&emit_state, tok);
+        break;
     case TT_MOV:
         state->last = tok->type;
         emit_osmx64(&emit_state, tok);
-- 
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