add branch instructions, no tests yet

crates/cpu/src/decoder/simple_power_isa.rs

@@ -4,8 +4,8 @@
 use crate::{
     config::CpuConfig,
     instruction::{
-        AddSubMOp, CompareMOp, CompareMode, LogicalMOp, MOp, MOpDestReg, MOpRegNum, MoveRegMOp,
-        OutputIntegerMode,
+        AddSubMOp, BranchMOp, CompareMOp, CompareMode, ConditionMode, LogicalMOp, MOp, MOpDestReg,
+        MOpRegNum, MoveRegMOp, OutputIntegerMode,
     },
     powerisa_instructions_xml::{
         InstructionBitFieldName, InstructionBitFieldsInner, Instructions, TextLineItem,
@@ -179,6 +179,8 @@ macro_rules! impl_fields {
 impl_fields! {
     #[name = "BF"]
     struct FieldBF(FieldCrf);
+    #[name = "BI"]
+    struct FieldBI(FieldCrBit);
     #[name = "RA"]
     struct FieldRA(FieldGpr);
     #[name = "RB"]
@@ -187,6 +189,10 @@ impl_fields! {
     struct FieldRS(FieldGpr);
     #[name = "RT"]
     struct FieldRT(FieldGpr);
+    #[name = "BD"]
+    struct FieldBD(SInt<14>);
+    #[name = "LI"]
+    struct FieldLI(SInt<24>);
     #[name = "SI"]
     struct FieldSI(SInt<16>);
     #[name = "si0"]
@@ -201,8 +207,16 @@ impl_fields! {
     struct FieldAddPcISD1(UInt<5>);
     #[name = "d2"]
     struct FieldAddPcISD2(UInt<1>);
+    #[name = "BH"]
+    struct FieldBH(UInt<2>);
+    #[name = "BO"]
+    struct FieldBO(UInt<5>);
+    #[name = "AA"]
+    struct FieldAA(Bool);
     #[name = "L"]
     struct FieldL(Bool);
+    #[name = "LK"]
+    struct FieldLK(Bool);
     #[name = "OE"]
     struct FieldOE(Bool);
     #[name = "R"]
@@ -223,6 +237,12 @@ struct FieldCrf {
     reg_num: UInt<3>,
 }
 
+/// condition register bit
+#[hdl]
+struct FieldCrBit {
+    bit_num: UInt<5>,
+}
+
 fn gpr(this: impl ToExpr<Type = FieldGpr>) -> Expr<MOpRegNum> {
     MOpRegNum::power_isa_gpr_reg(this.to_expr().reg_num)
 }
@@ -235,6 +255,26 @@ fn crf(this: impl ToExpr<Type = FieldCrf>) -> Expr<MOpRegNum> {
     MOpRegNum::power_isa_cr_reg(this.to_expr().reg_num)
 }
 
+#[hdl]
+fn cr_bit(cr_bit: impl ToExpr<Type = FieldCrBit>) -> (Expr<MOpRegNum>, Expr<ConditionMode>) {
+    let cr_bit = cr_bit.to_expr();
+    #[hdl]
+    let condition_mode = wire();
+    let field_bit = cr_bit.bit_num.cast_to_static::<UInt<2>>();
+    let field_num = (cr_bit.bit_num >> 2).cast_to_static::<UInt<3>>();
+    #[hdl]
+    if field_bit.cmp_eq(0_hdl_u2) {
+        connect(condition_mode, ConditionMode.SLt());
+    } else if field_bit.cmp_eq(1_hdl_u2) {
+        connect(condition_mode, ConditionMode.SGt());
+    } else if field_bit.cmp_eq(2_hdl_u2) {
+        connect(condition_mode, ConditionMode.Eq());
+    } else {
+        connect(condition_mode, ConditionMode.Overflow());
+    }
+    (MOpRegNum::power_isa_cr_reg(field_num), condition_mode)
+}
+
 impl DecodeState {
     fn form(&self) -> &'static str {
         let mut title_words = self
@@ -439,7 +479,160 @@ impl DecodeState {
         }
     }
     fn decode_b_ba_bl_bla(&mut self) {
-        // TODO
+        self.decode_scope(|this, (FieldLI(li), FieldAA(aa), FieldLK(lk))| {
+            connect(
+                ArrayVec::len(this.output),
+                1usize.cast_to_static::<Length<_>>(),
+            );
+            connect(
+                this.output[0],
+                BranchMOp::branch_i(
+                    MOpDestReg::new(
+                        [if this.mnemonic.contains('l') {
+                            MOpRegNum::power_isa_lr_reg()
+                        } else {
+                            MOpRegNum::const_zero()
+                        }],
+                        [],
+                    ),
+                    MOpRegNum::const_zero().value,
+                    (li << 2).cast_to_static(),
+                    !aa,
+                    lk,
+                    false,
+                ),
+            );
+        });
+    }
+    #[hdl]
+    fn decode_bc_bclr_bcctr_bctar(&mut self) {
+        let addr_reg = match self.mnemonic {
+            "bc" | "bca" | "bcl" | "bcla" => None,
+            "bclr" | "bclrl" => Some(MOpRegNum::power_isa_lr_reg()),
+            "bcctr" | "bcctrl" => Some(MOpRegNum::power_isa_ctr_reg()),
+            "bctar" | "bctarl" => Some(MOpRegNum::power_isa_tar_reg()),
+            _ => unreachable!(),
+        };
+        let body = |this: &mut DecodeState,
+                    bo: Expr<UInt<5>>,
+                    bi: Expr<FieldCrBit>,
+                    is_ret: Expr<Bool>,
+                    bd: Option<Expr<SInt<14>>>,
+                    aa: Option<Expr<Bool>>,
+                    lk: Expr<Bool>| {
+            let use_eq_for_ctr_compare = bo[1]; // BO_3 in specification
+            let no_ctr = bo[2]; // BO_2 in specification
+            let expected_cr_bit_value = bo[3]; // BO_1 in specification
+            let no_cr_bit = bo[4]; // BO_0 in specification
+            let (cr_field, condition_mode) = cr_bit(bi);
+            #[hdl]
+            let branch_mop = wire();
+            #[hdl]
+            let branch_lr_dest_reg = wire();
+            connect(branch_lr_dest_reg, MOpRegNum::const_zero());
+            #[hdl]
+            if lk {
+                connect(branch_lr_dest_reg, MOpRegNum::power_isa_lr_reg());
+            }
+            #[hdl]
+            let branch_ctr_reg: MOpRegNum = wire();
+            let dest = MOpDestReg::new([branch_lr_dest_reg], []);
+            let src1 = addr_reg.unwrap_or_else(|| MOpRegNum::const_zero()).value;
+            let imm = (bd.unwrap_or(0_hdl_i14) << 2).cast_to_static();
+            let invert_src2_eq_zero = !use_eq_for_ctr_compare;
+            let pc_relative = match aa {
+                Some(aa) => !aa,
+                None => addr_reg.is_none().to_expr(),
+            };
+            #[hdl]
+            if no_cr_bit {
+                connect(
+                    branch_mop,
+                    BranchMOp::branch_ctr(
+                        dest,
+                        src1,
+                        branch_ctr_reg.value,
+                        imm,
+                        invert_src2_eq_zero,
+                        pc_relative,
+                        lk,
+                        is_ret,
+                    ),
+                );
+            } else {
+                connect(
+                    branch_mop,
+                    BranchMOp::branch_cond_ctr(
+                        dest,
+                        [cr_field.value, src1, branch_ctr_reg.value],
+                        imm,
+                        !expected_cr_bit_value,
+                        condition_mode,
+                        invert_src2_eq_zero,
+                        pc_relative,
+                        lk,
+                        is_ret,
+                    ),
+                );
+            }
+            #[hdl]
+            if no_ctr {
+                connect(
+                    ArrayVec::len(this.output),
+                    1usize.cast_to_static::<Length<_>>(),
+                );
+                connect(this.output[0], branch_mop);
+                connect(branch_ctr_reg, MOpRegNum::const_zero());
+            } else {
+                connect(
+                    ArrayVec::len(this.output),
+                    1usize.cast_to_static::<Length<_>>(),
+                );
+                connect(
+                    this.output[0],
+                    AddSubMOp::add_sub_i(
+                        MOpDestReg::new([MOpRegNum::power_isa_ctr_reg()], []),
+                        [
+                            MOpRegNum::power_isa_ctr_reg().value,
+                            MOpRegNum::const_zero().value,
+                        ],
+                        (-1).cast_to_static::<SInt<_>>(),
+                        OutputIntegerMode.Full64(),
+                        false,
+                        false,
+                        false,
+                        false,
+                    ),
+                );
+                connect(this.output[1], branch_mop);
+                connect(branch_ctr_reg, MOpRegNum::power_isa_ctr_reg());
+            }
+        };
+        if addr_reg.is_some() {
+            self.decode_scope(
+                |this, (FieldBO(bo), FieldBI(bi), FieldBH(bh), FieldLK(lk))| {
+                    body(
+                        this,
+                        bo,
+                        bi,
+                        if this.mnemonic.starts_with("bclr") {
+                            bh.cmp_eq(0u8)
+                        } else {
+                            false.to_expr()
+                        },
+                        None,
+                        None,
+                        lk,
+                    )
+                },
+            );
+        } else {
+            self.decode_scope(
+                |this, (FieldBO(bo), FieldBI(bi), FieldBD(bd), FieldAA(aa), FieldLK(lk))| {
+                    body(this, bo, bi, false.to_expr(), Some(bd), Some(aa), lk)
+                },
+            );
+        }
     }
     #[hdl]
     fn decode_addi_paddi(&mut self) {
@@ -1165,18 +1358,12 @@ type DecodeFn = fn(&mut DecodeState);
 
 const DECODE_FNS: &[(&[&str], DecodeFn)] = &[
     (&["b", "ba", "bl", "bla"], DecodeState::decode_b_ba_bl_bla),
-    (&["bc", "bca", "bcl", "bcla"], |_state| {
-        // TODO
-    }),
-    (&["bclr", "bclrl"], |_state| {
-        // TODO
-    }),
-    (&["bcctr", "bcctrl"], |_state| {
-        // TODO
-    }),
-    (&["bctar", "bctarl"], |_state| {
-        // TODO
-    }),
+    (
+        &[
+            "bc", "bca", "bcl", "bcla", "bclr", "bclrl", "bcctr", "bcctrl", "bctar", "bctarl",
+        ],
+        DecodeState::decode_bc_bclr_bcctr_bctar,
+    ),
     (
         &[
             "crand", "crnand", "cror", "crxor", "crnor", "creqv", "crandc", "crorc",

crates/cpu/src/instruction.rs

@@ -3,7 +3,7 @@
 use crate::{unit::UnitMOp, util::range_u32_len};
 use fayalite::{
     expr::{HdlPartialEqImpl, ops::ArrayLiteral},
-    intern::Interned,
+    intern::{Intern, InternSlice, Interned},
     module::wire_with_loc,
     prelude::*,
     ty::StaticType,
@@ -1101,13 +1101,195 @@ impl<DestReg: Type, SrcRegWidth: Size> CompareMOp<DestReg, SrcRegWidth, ConstUsi
     }
 }
 
+#[hdl]
+pub enum ConditionMode {
+    Eq,
+    ULt,
+    UGt,
+    SLt,
+    SGt,
+    Sign,
+    Overflow,
+    Parity,
+}
+
+impl HdlPartialEqImpl<Self> for ConditionMode {
+    #[track_caller]
+    fn cmp_value_eq(
+        lhs: Self,
+        lhs_value: Cow<'_, Self::SimValue>,
+        rhs: Self,
+        rhs_value: Cow<'_, Self::SimValue>,
+    ) -> bool {
+        SimValue::opaque(&SimValue::from_value(lhs, lhs_value.into_owned()))
+            == SimValue::opaque(&SimValue::from_value(rhs, rhs_value.into_owned()))
+    }
+
+    #[track_caller]
+    fn cmp_sim_value_eq(
+        lhs: Cow<'_, SimValue<Self>>,
+        rhs: Cow<'_, SimValue<Self>>,
+    ) -> SimValue<Bool> {
+        (SimValue::opaque(&lhs) == SimValue::opaque(&rhs)).to_sim_value()
+    }
+
+    #[track_caller]
+    fn cmp_sim_value_ne(
+        lhs: Cow<'_, SimValue<Self>>,
+        rhs: Cow<'_, SimValue<Self>>,
+    ) -> SimValue<Bool> {
+        (SimValue::opaque(&lhs) != SimValue::opaque(&rhs)).to_sim_value()
+    }
+
+    #[track_caller]
+    fn cmp_expr_eq(lhs: Expr<Self>, rhs: Expr<Self>) -> Expr<Bool> {
+        lhs.cast_to_bits().cmp_eq(rhs.cast_to_bits())
+    }
+}
+
 common_mop_struct! {
-    #[mapped(<NewDestReg, NewSrcRegWidth> BranchMOp<NewDestReg, NewSrcRegWidth>)]
+    #[mapped(<NewDestReg, NewSrcRegWidth> BranchMOp<NewDestReg, NewSrcRegWidth, SrcCount>)]
     #[hdl(cmp_eq)]
-    pub struct BranchMOp<DestReg: Type, SrcRegWidth: Size> {
+    /// `src0` is the value used for reading flags from.
+    /// `src1 + imm + if pc_relative { pc } else { 0 }` is the target address.
+    /// `src2` (if present) is the counter to compare against zero.
+    /// The branch is taken only if all of `src2` (if present) and `src0`'s conditions pass
+    /// The output value is the next instruction's address used for a return address when this is a call.
+    pub struct BranchMOp<DestReg: Type, SrcRegWidth: Size, SrcCount: KnownSize> {
         #[common]
-        pub alu_common: AluCommonMOp<DestReg, SrcRegWidth, ConstUsize<2>>,
-        pub lut: UInt<4>,
+        pub common: CommonMOp<ConstUsize<0>, DestReg, SrcRegWidth, SrcCount>,
+        pub invert_src0_cond: Bool,
+        pub src0_cond_mode: ConditionMode,
+        /// `src2`'s condition passes if `src2`'s value `== 0`.
+        /// However, if `invert_src2_eq_zero` is set, then the comparison is instead `!= 0`.
+        pub invert_src2_eq_zero: Bool,
+        pub pc_relative: Bool,
+        pub is_call: Bool,
+        pub is_ret: Bool,
+    }
+}
+
+impl<DestReg: Type, SrcRegWidth: Size> BranchMOp<DestReg, SrcRegWidth, ConstUsize<2>> {
+    #[hdl]
+    pub fn branch_cond_i<Target: MOpTrait>(
+        dest: impl ToExpr<Type = DestReg>,
+        src: impl ToExpr<Type = Array<UIntType<SrcRegWidth>, 2>>,
+        imm: impl ToExpr<Type = SInt<{ COMMON_MOP_2_IMM_WIDTH }>>,
+        invert_src0_cond: impl ToExpr<Type = Bool>,
+        src0_cond_mode: impl ToExpr<Type = ConditionMode>,
+        pc_relative: impl ToExpr<Type = Bool>,
+        is_call: impl ToExpr<Type = Bool>,
+        is_ret: impl ToExpr<Type = Bool>,
+    ) -> Expr<Target>
+    where
+        Self: MOpInto<Target>,
+    {
+        MOpInto::mop_into(
+            #[hdl]
+            BranchMOp {
+                common: CommonMOp::new(0_hdl_u0, dest, src, Expr::as_dyn_int(imm.to_expr())),
+                invert_src0_cond,
+                src0_cond_mode,
+                invert_src2_eq_zero: false,
+                pc_relative,
+                is_call,
+                is_ret,
+            },
+        )
+    }
+    #[hdl]
+    pub fn branch_i<Target: MOpTrait>(
+        dest: impl ToExpr<Type = DestReg>,
+        src1: impl ToExpr<Type = UIntType<SrcRegWidth>>,
+        imm: impl ToExpr<Type = SInt<{ COMMON_MOP_2_IMM_WIDTH }>>,
+        pc_relative: impl ToExpr<Type = Bool>,
+        is_call: impl ToExpr<Type = Bool>,
+        is_ret: impl ToExpr<Type = Bool>,
+    ) -> Expr<Target>
+    where
+        Self: MOpInto<Target>,
+    {
+        let src1 = src1.to_expr();
+        Self::branch_cond_i(
+            dest,
+            ArrayLiteral::new(
+                src1.ty(),
+                [src1.ty().zero().to_expr(), src1]
+                    .into_iter()
+                    .map(Expr::canonical)
+                    .collect(),
+            ),
+            imm,
+            true,
+            ConditionMode.ULt(),
+            pc_relative,
+            is_call,
+            is_ret,
+        )
+    }
+}
+
+impl<DestReg: Type, SrcRegWidth: Size> BranchMOp<DestReg, SrcRegWidth, ConstUsize<3>> {
+    #[hdl]
+    pub fn branch_cond_ctr<Target: MOpTrait>(
+        dest: impl ToExpr<Type = DestReg>,
+        src: impl ToExpr<Type = Array<UIntType<SrcRegWidth>, 3>>,
+        imm: impl ToExpr<Type = SInt<{ COMMON_MOP_3_IMM_WIDTH }>>,
+        invert_src0_cond: impl ToExpr<Type = Bool>,
+        src0_cond_mode: impl ToExpr<Type = ConditionMode>,
+        invert_src2_eq_zero: impl ToExpr<Type = Bool>,
+        pc_relative: impl ToExpr<Type = Bool>,
+        is_call: impl ToExpr<Type = Bool>,
+        is_ret: impl ToExpr<Type = Bool>,
+    ) -> Expr<Target>
+    where
+        Self: MOpInto<Target>,
+    {
+        MOpInto::mop_into(
+            #[hdl]
+            BranchMOp {
+                common: CommonMOp::new(0_hdl_u0, dest, src, Expr::as_dyn_int(imm.to_expr())),
+                invert_src0_cond,
+                src0_cond_mode,
+                invert_src2_eq_zero,
+                pc_relative,
+                is_call,
+                is_ret,
+            },
+        )
+    }
+    #[hdl]
+    pub fn branch_ctr<Target: MOpTrait>(
+        dest: impl ToExpr<Type = DestReg>,
+        src1: impl ToExpr<Type = UIntType<SrcRegWidth>>,
+        src2: impl ToExpr<Type = UIntType<SrcRegWidth>>,
+        imm: impl ToExpr<Type = SInt<{ COMMON_MOP_3_IMM_WIDTH }>>,
+        invert_src2_eq_zero: impl ToExpr<Type = Bool>,
+        pc_relative: impl ToExpr<Type = Bool>,
+        is_call: impl ToExpr<Type = Bool>,
+        is_ret: impl ToExpr<Type = Bool>,
+    ) -> Expr<Target>
+    where
+        Self: MOpInto<Target>,
+    {
+        let src1 = src1.to_expr();
+        Self::branch_cond_ctr(
+            dest,
+            ArrayLiteral::new(
+                src1.ty(),
+                [src1.ty().zero().to_expr(), src1, src2.to_expr()]
+                    .into_iter()
+                    .map(Expr::canonical)
+                    .collect(),
+            ),
+            imm,
+            true,
+            ConditionMode.ULt(),
+            invert_src2_eq_zero,
+            pc_relative,
+            is_call,
+            is_ret,
+        )
     }
 }
 
@@ -1121,6 +1303,8 @@ mop_enum! {
         LogicalI(LogicalMOp<DestReg, SrcRegWidth, ConstUsize<1>>),
         Compare(CompareMOp<DestReg, SrcRegWidth, ConstUsize<2>>),
         CompareI(CompareMOp<DestReg, SrcRegWidth, ConstUsize<1>>),
+        Branch(BranchMOp<DestReg, SrcRegWidth, ConstUsize<3>>),
+        BranchI(BranchMOp<DestReg, SrcRegWidth, ConstUsize<2>>),
     }
 }
 

crates/cpu/src/instruction/power_isa.rs

@@ -27,8 +27,29 @@ pub struct PowerIsaCrBitNum {
 
 impl MOpRegNum {
     pub const POWER_ISA_LR_REG_NUM: u32 = 1;
+    #[hdl]
+    pub fn power_isa_lr_reg() -> Expr<Self> {
+        #[hdl]
+        Self {
+            value: Self::POWER_ISA_LR_REG_NUM.cast_to_static::<UInt<_>>(),
+        }
+    }
     pub const POWER_ISA_CTR_REG_NUM: u32 = 2;
+    #[hdl]
+    pub fn power_isa_ctr_reg() -> Expr<Self> {
+        #[hdl]
+        Self {
+            value: Self::POWER_ISA_CTR_REG_NUM.cast_to_static::<UInt<_>>(),
+        }
+    }
     pub const POWER_ISA_TAR_REG_NUM: u32 = 3;
+    #[hdl]
+    pub fn power_isa_tar_reg() -> Expr<Self> {
+        #[hdl]
+        Self {
+            value: Self::POWER_ISA_TAR_REG_NUM.cast_to_static::<UInt<_>>(),
+        }
+    }
 
     /// SO, OV, and OV32 XER bits -- in [`PRegValue.flags`]
     ///

crates/cpu/src/unit/alu_branch.rs

@@ -4,8 +4,8 @@
 use crate::{
     config::CpuConfig,
     instruction::{
-        AddSubMOp, AluBranchMOp, AluCommonMOp, COMMON_MOP_SRC_LEN, CommonMOp, CompareMOp,
-        LogicalMOp, MOpTrait, OutputIntegerMode, RenamedMOp, UnitOutRegNum,
+        AddSubMOp, AluBranchMOp, AluCommonMOp, BranchMOp, COMMON_MOP_SRC_LEN, CommonMOp,
+        CompareMOp, LogicalMOp, MOpTrait, OutputIntegerMode, RenamedMOp, UnitOutRegNum,
     },
     register::{FlagsMode, PRegFlagsPowerISA, PRegFlagsX86, PRegValue},
     unit::{
@@ -272,6 +272,21 @@ fn compare<SrcCount: KnownSize>(
     }
 }
 
+#[hdl]
+fn branch<SrcCount: KnownSize>(
+    mop: Expr<BranchMOp<UnitOutRegNum<DynSize>, DynSize, SrcCount>>,
+    pc: Expr<UInt<64>>,
+    flags_mode: Expr<FlagsMode>,
+    src_values: Expr<Array<PRegValue, { COMMON_MOP_SRC_LEN }>>,
+) -> Expr<UnitResultCompleted<()>> {
+    // TODO: finish
+    #[hdl]
+    UnitResultCompleted::<_> {
+        value: PRegValue::zeroed(),
+        extra_out: (),
+    }
+}
+
 #[hdl_module]
 pub fn alu_branch(config: &CpuConfig, unit_index: usize) {
     #[hdl]
@@ -415,6 +430,42 @@ pub fn alu_branch(config: &CpuConfig, unit_index: usize) {
                     },
                 ),
             ),
+            AluBranchMOp::<_, _>::Branch(mop) => connect(
+                unit_base.execute_end,
+                HdlSome(
+                    #[hdl]
+                    ExecuteEnd::<_, _> {
+                        unit_output: #[hdl]
+                        UnitOutput::<_, _> {
+                            which: MOpTrait::dest_reg(mop),
+                            result: UnitResult[()].Completed(branch(
+                                mop,
+                                pc,
+                                global_state.flags_mode,
+                                src_values,
+                            )),
+                        },
+                    },
+                ),
+            ),
+            AluBranchMOp::<_, _>::BranchI(mop) => connect(
+                unit_base.execute_end,
+                HdlSome(
+                    #[hdl]
+                    ExecuteEnd::<_, _> {
+                        unit_output: #[hdl]
+                        UnitOutput::<_, _> {
+                            which: MOpTrait::dest_reg(mop),
+                            result: UnitResult[()].Completed(branch(
+                                mop,
+                                pc,
+                                global_state.flags_mode,
+                                src_values,
+                            )),
+                        },
+                    },
+                ),
+            ),
         }
     }
 }