oasm: Add encoding for MRO type instructions

This commit introduces encoding logic for 4 additional instructions:

- MROB (Mask Register Over [byte])
- MROW (Mask Register Over [word])
- MROD (Mask Register Over [dword])
- MROQ (Mask Register Over [qword])

This instruction is used to fill a register with a specific length of
zeros or ones. For example, to fill a register (e.g., x2) with 16-bits
of 1s:

--
!!
!! Clear bits x2[7:0]... Mrrp,,
!! mrow!!
!!
mrow x2, #1
--

Similarly, an operand of zero sets it to zero. For example, to clear an
entire 64-bit register with zeros. Something like this can be done:

--
mroq x1, #0
--

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

2 files changed, 26 insertions, 0 deletions

diff --git a/usr.bin/oasm/include/oasm/emit.h b/usr.bin/oasm/include/oasm/emit.h
index dab63d0..0236967 100644
--- a/usr.bin/oasm/include/oasm/emit.h
+++ b/usr.bin/oasm/include/oasm/emit.h
@@ -62,6 +62,10 @@
 #define OSMX64_MOV_IMM  0x13    /* Data move operation from IMM */
 #define OSMX64_HLT      0x14    /* Halt the processor */
 #define OSMX64_BR       0x15    /* Branch */
+#define OSMX64_MROB     0x16    /* Mask register over byte */
+#define OSMX64_MROW     0x17    /* Mask register over word */
+#define OSMX64_MROD     0x18    /* Mask register over dword */
+#define OSMX64_MROQ     0x19    /* Mask register over qword */
 
 /*
  * OSMX64 register definitions
diff --git a/usr.bin/oasm/include/oasm/lex.h b/usr.bin/oasm/include/oasm/lex.h
index 69e50a1..fa82398 100644
--- a/usr.bin/oasm/include/oasm/lex.h
+++ b/usr.bin/oasm/include/oasm/lex.h
@@ -97,6 +97,10 @@ typedef enum {
     TT_DIV,         /* 'div' */
     TT_HLT,         /* 'hlt' */
     TT_BR,          /* 'br'  */
+    TT_MROB,        /* 'mrob' */
+    TT_MROW,        /* 'mrow' */
+    TT_MROD,        /* 'mrod' */
+    TT_MROQ,        /* 'mroq' */
 
     /* Register ops */
     TT_MOV,         /* 'mov' */
@@ -156,4 +160,22 @@ tok_is_xreg(tt_t tok)
     return false;
 }
 
+/*
+ * Check if a token is of an MRO type
+ * instruction. Returns true on match.
+ */
+__always_inline static inline bool
+lex_is_mro(tt_t tok)
+{
+    switch (tok) {
+    case TT_MROB:
+    case TT_MROW:
+    case TT_MROD:
+    case TT_MROQ:
+        return true;
+    }
+
+    return false;
+}
+
 #endif  /* !_OASM_LEX_H_ */