BRANCHING (TURING COMPLETE????)

src/compiler/arch/riscv/instr/base.rs

@@ -22,6 +22,7 @@ pub const IMM_OP: u32 = 0b0010011;
 pub const OP: u32 = 0b0110011;
 pub const JAL: u32 = 0b1101111;
 pub const JALR: u32 = 0b1100111;
+pub const BRANCH: u32 = 0b1100011;
 
 pub type Funct3 = Bits32<2, 0>;
 pub type Funct7 = Bits32<6, 0>;
@@ -59,7 +60,7 @@ pub const fn b_type(rs2: Reg, rs1: Reg, funct3: Funct3, imm: Bits32<12, 1>, opco
         + (imm.bits(10, 5) << 25)
         + (rs2.val() << 20)
         + (rs1.val() << 15)
-        + (funct3.val() << 8)
+        + (funct3.val() << 12)
         + (imm.bits(4, 1) << 8)
         + (imm.bit(11) << 7)
         + opcode)

src/compiler/arch/riscv/instr/rv32i.rs

@@ -63,6 +63,28 @@ pub mod width {
     }
 }
 
+pub mod branch {
+    use super::*;
+    pub const EQ: Funct3 = Funct3::new(0b000);
+    pub const NE: Funct3 = Funct3::new(0b001);
+    pub const LT: Funct3 = Funct3::new(0b100);
+    pub const GE: Funct3 = Funct3::new(0b101);
+    pub const LTU: Funct3 = Funct3::new(0b110);
+    pub const GEU: Funct3 = Funct3::new(0b111);
+
+    pub fn str(f: Funct3) -> &'static str {
+        match f {
+            EQ => "eq",
+            NE => "ne",
+            LT => "lt",
+            GE => "ge",
+            LTU => "ltu",
+            GEU => "geu",
+            _ => "?",
+        }
+    }
+}
+
 pub const fn ecall() -> RawInstruction {
     i_type(Bits32::new(0), zero, Bits32::new(0), zero, SYSTEM)
 }
@@ -94,3 +116,7 @@ pub const fn j(offset: BitsI32<20, 1>) -> RawInstruction {
 pub const fn ret() -> RawInstruction {
     jalr(zero, BitsI32::new(0), ra)
 }
+
+pub const fn branch(typ: Funct3, left: Reg, right: Reg, offset: BitsI32<12, 1>) -> RawInstruction {
+    b_type(right, left, typ, offset.to_u(), BRANCH)
+}