From b10cb715610d0186b70765a152baaf71e192a9f1 Mon Sep 17 00:00:00 2001
From: Mathias Magnusson <mathias@magnusson.space>
Date: Sun, 1 Jun 2025 01:38:13 +0200
Subject: codegen: add RV64M extension

---
 src/codegen.zig | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

(limited to 'src')

diff --git a/src/codegen.zig b/src/codegen.zig
index bb244da..b9f39c9 100644
--- a/src/codegen.zig
+++ b/src/codegen.zig
@@ -122,6 +122,77 @@ const Instruction = packed union {
         return R.init(0b0110011, rd, 3, rs1, rs2, 0);
     }
 
+    // start M extension
+
+    /// Multiply.
+    /// rd = rs1 * r2
+    fn mul(rd: Register, rs1: Register, rs2: Register) Self {
+        return R.init(0b0110011, rd, 0, rs1, rs2, 1);
+    }
+    /// Multiply, get high bits.
+    /// rd = (rs1 * r2) >> 64
+    fn mulh(rd: Register, rs1: Register, rs2: Register) Self {
+        return R.init(0b0110011, rd, 1, rs1, rs2, 1);
+    }
+    /// Multiply signed `rs1` by unsigned `rs2`, get high bits.
+    /// rd = (rs1 * r2) >> 64
+    fn mulhsu(rd: Register, rs1: Register, rs2: Register) Self {
+        return R.init(0b0110011, rd, 2, rs1, rs2, 1);
+    }
+    /// Multiply unsigned `rs1` by unsigned `rs2`, get high bits.
+    /// rd = (rs1 * r2) >> 64
+    fn mulhu(rd: Register, rs1: Register, rs2: Register) Self {
+        return R.init(0b0110011, rd, 3, rs1, rs2, 1);
+    }
+    /// Divide, signed.
+    /// rd = rs1 / r2
+    fn div(rd: Register, rs1: Register, rs2: Register) Self {
+        return R.init(0b0110011, rd, 4, rs1, rs2, 1);
+    }
+    /// Divide, unsigned.
+    /// rd = rs1 / r2
+    fn divu(rd: Register, rs1: Register, rs2: Register) Self {
+        return R.init(0b0110011, rd, 5, rs1, rs2, 1);
+    }
+    /// Remainder, unsigned.
+    /// rd = rs1 % r2
+    fn rem(rd: Register, rs1: Register, rs2: Register) Self {
+        return R.init(0b0110011, rd, 6, rs1, rs2, 1);
+    }
+    /// Remainder, signed (modulus).
+    /// rd = rs1 % r2
+    fn remu(rd: Register, rs1: Register, rs2: Register) Self {
+        return R.init(0b0110011, rd, 7, rs1, rs2, 1);
+    }
+
+    // end M extension
+
+    /// Multiply words.
+    /// rd = rs1 * r2
+    fn mulw(rd: Register, rs1: Register, rs2: Register) Self {
+        return R.init(0b0111011, rd, 0, rs1, rs2, 1);
+    }
+    /// Divide words, signed.
+    /// rd = rs1 / r2
+    fn divw(rd: Register, rs1: Register, rs2: Register) Self {
+        return R.init(0b0111011, rd, 4, rs1, rs2, 1);
+    }
+    /// Divide words, unsigned.
+    /// rd = rs1 / r2
+    fn divuw(rd: Register, rs1: Register, rs2: Register) Self {
+        return R.init(0b0111011, rd, 5, rs1, rs2, 1);
+    }
+    /// Remainder of words, unsigned.
+    /// rd = rs1 % r2
+    fn remw(rd: Register, rs1: Register, rs2: Register) Self {
+        return R.init(0b0111011, rd, 6, rs1, rs2, 1);
+    }
+    /// Remainder of words, signed (modulus).
+    /// rd = rs1 % r2
+    fn remuw(rd: Register, rs1: Register, rs2: Register) Self {
+        return R.init(0b0111011, rd, 7, rs1, rs2, 1);
+    }
+
     const I = packed struct(u32) {
         opcode: Opcode,
         rd: Register,
-- 
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