feat(avm): cpp msm changes (#7056)

Please read [contributing guidelines](CONTRIBUTING.md) and remove this
line.

barretenberg/cpp/src/barretenberg/vm/avm_trace/avm_execution.cpp

@@ -677,6 +677,13 @@ std::vector<Row> Execution::gen_trace(std::vector<Instruction> const& instructio
                                     std::get<uint32_t>(inst.operands.at(6)),
                                     std::get<uint32_t>(inst.operands.at(7)));
             break;
+        case OpCode::MSM:
+            trace_builder.op_variable_msm(std::get<uint8_t>(inst.operands.at(0)),
+                                          std::get<uint32_t>(inst.operands.at(1)),
+                                          std::get<uint32_t>(inst.operands.at(2)),
+                                          std::get<uint32_t>(inst.operands.at(3)),
+                                          std::get<uint32_t>(inst.operands.at(4)));
+            break;
         case OpCode::REVERT:
             trace_builder.op_revert(std::get<uint8_t>(inst.operands.at(0)),
                                     std::get<uint32_t>(inst.operands.at(1)),

barretenberg/cpp/src/barretenberg/vm/avm_trace/avm_opcode.cpp

@@ -144,6 +144,10 @@ std::string to_string(OpCode opcode)
         return "SHA256";
     case OpCode::PEDERSEN:
         return "PEDERSEN";
+    case OpCode::ECADD:
+        return "ECADD";
+    case OpCode::MSM:
+        return "MSM";
     case OpCode::TORADIXLE:
         return "TORADIXLE";
     case OpCode::SHA256COMPRESSION:

barretenberg/cpp/src/barretenberg/vm/avm_trace/avm_trace.cpp

@@ -14,7 +14,9 @@
 #include <vector>
 
 #include "barretenberg/common/throw_or_abort.hpp"
+#include "barretenberg/ecc/curves/grumpkin/grumpkin.hpp"
 #include "barretenberg/numeric/uint256/uint256.hpp"
+#include "barretenberg/polynomials/univariate.hpp"
 #include "barretenberg/vm/avm_trace/avm_common.hpp"
 #include "barretenberg/vm/avm_trace/avm_helper.hpp"
 #include "barretenberg/vm/avm_trace/avm_opcode.hpp"
@@ -3632,6 +3634,255 @@ void AvmTraceBuilder::op_ec_add(uint8_t indirect,
                           FF(internal_return_ptr),
                           { result.is_point_at_infinity() });
 }
+
+// This function is a bit overloaded with logic around reconstructing points and scalars that could probably be moved to
+// the gadget at some stage (although this is another temporary gadget..)
+void AvmTraceBuilder::op_variable_msm(uint8_t indirect,
+                                      uint32_t points_offset,
+                                      uint32_t scalars_offset,
+                                      uint32_t output_offset,
+                                      uint32_t point_length_offset)
+{
+    auto clk = static_cast<uint32_t>(main_trace.size()) + 1;
+    // This will all get refactored as part of the indirection refactor
+    bool tag_match = true;
+    uint32_t direct_points_offset = points_offset;
+    uint32_t direct_scalars_offset = scalars_offset;
+    uint32_t direct_output_offset = output_offset;
+    // Resolve the indirects
+    bool indirect_points_flag = is_operand_indirect(indirect, 0);
+    bool indirect_scalars_flag = is_operand_indirect(indirect, 1);
+    bool indirect_output_flag = is_operand_indirect(indirect, 2);
+
+    // Read in the points first
+    if (indirect_points_flag) {
+        auto read_ind_a =
+            mem_trace_builder.indirect_read_and_load_from_memory(call_ptr, clk, IndirectRegister::IND_A, points_offset);
+        direct_points_offset = uint32_t(read_ind_a.val);
+        tag_match = tag_match && read_ind_a.tag_match;
+    }
+
+    auto read_points = mem_trace_builder.read_and_load_from_memory(
+        call_ptr, clk, IntermRegister::IA, direct_points_offset, AvmMemoryTag::FF, AvmMemoryTag::U0);
+
+    // Read in the scalars
+    if (indirect_scalars_flag) {
+        auto read_ind_b = mem_trace_builder.indirect_read_and_load_from_memory(
+            call_ptr, clk, IndirectRegister::IND_B, scalars_offset);
+        direct_scalars_offset = uint32_t(read_ind_b.val);
+        tag_match = tag_match && read_ind_b.tag_match;
+    }
+    auto read_scalars = mem_trace_builder.read_and_load_from_memory(
+        call_ptr, clk, IntermRegister::IB, direct_scalars_offset, AvmMemoryTag::FF, AvmMemoryTag::U0);
+
+    // In the refactor we will have the read_slice function handle indirects as well
+    main_trace.push_back(Row{
+        .avm_main_clk = clk,
+        .avm_main_ia = read_points.val,
+        .avm_main_ib = read_scalars.val,
+        .avm_main_ind_a = indirect_points_flag ? FF(points_offset) : FF(0),
+        .avm_main_ind_b = indirect_scalars_flag ? FF(scalars_offset) : FF(0),
+        .avm_main_ind_op_a = FF(static_cast<uint32_t>(indirect_points_flag)),
+        .avm_main_ind_op_b = FF(static_cast<uint32_t>(indirect_scalars_flag)),
+        .avm_main_internal_return_ptr = FF(internal_return_ptr),
+        .avm_main_mem_idx_a = FF(direct_points_offset),
+        .avm_main_mem_idx_b = FF(direct_scalars_offset),
+        .avm_main_mem_op_a = FF(1),
+        .avm_main_mem_op_b = FF(1),
+        .avm_main_pc = FF(pc++),
+        .avm_main_r_in_tag = FF(static_cast<uint32_t>(AvmMemoryTag::FF)),
+        .avm_main_tag_err = FF(static_cast<uint32_t>(!tag_match)),
+    });
+    clk++;
+
+    // Read the points length (different row since it has a different memory tag)
+    auto points_length_read = mem_trace_builder.read_and_load_from_memory(
+        call_ptr, clk, IntermRegister::IA, point_length_offset, AvmMemoryTag::U32, AvmMemoryTag::U0);
+    main_trace.push_back(Row{
+        .avm_main_clk = clk,
+        .avm_main_ia = points_length_read.val,
+        .avm_main_internal_return_ptr = FF(internal_return_ptr),
+        .avm_main_mem_idx_a = FF(point_length_offset),
+        .avm_main_mem_op_a = FF(1),
+        .avm_main_pc = FF(pc),
+        .avm_main_r_in_tag = FF(static_cast<uint32_t>(AvmMemoryTag::U32)),
+        .avm_main_tag_err = FF(static_cast<uint32_t>(!points_length_read.tag_match)),
+    });
+    clk++;
+
+    // Points are stored as [x1, y1, inf1, x2, y2, inf2, ...] with the types [FF, FF, U8, FF, FF, U8, ...]
+    uint32_t num_points = uint32_t(points_length_read.val) / 3; // 3 elements per point
+    // We need to split up the reads due to the memory tags,
+    std::vector<FF> points_coords_vec;
+    std::vector<FF> points_inf_vec;
+    std::vector<FF> scalars_vec;
+    // Read the coordinates first, +2 since we read 2 points per row
+    for (uint32_t i = 0; i < num_points; i += 2) {
+        // We can read up to 4 coordinates per row (x1,y1,x2,y2)
+        // Each pair of coordinates are separated by 3 memory addressess
+        auto point_x1_read = mem_trace_builder.read_and_load_from_memory(
+            call_ptr, clk, IntermRegister::IA, direct_points_offset + i * 3, AvmMemoryTag::FF, AvmMemoryTag::U0);
+        auto point_y1_read = mem_trace_builder.read_and_load_from_memory(
+            call_ptr, clk, IntermRegister::IB, direct_points_offset + i * 3 + 1, AvmMemoryTag::FF, AvmMemoryTag::U0);
+        auto point_x2_read = mem_trace_builder.read_and_load_from_memory(
+            call_ptr, clk, IntermRegister::IC, direct_points_offset + (i + 1) * 3, AvmMemoryTag::FF, AvmMemoryTag::U0);
+        auto point_y2_read = mem_trace_builder.read_and_load_from_memory(call_ptr,
+                                                                         clk,
+                                                                         IntermRegister::ID,
+                                                                         direct_points_offset + (i + 1) * 3 + 1,
+                                                                         AvmMemoryTag::FF,
+                                                                         AvmMemoryTag::U0);
+        bool tag_match =
+            point_x1_read.tag_match && point_y1_read.tag_match && point_x2_read.tag_match && point_y2_read.tag_match;
+        points_coords_vec.insert(points_coords_vec.end(),
+                                 { point_x1_read.val, point_y1_read.val, point_x2_read.val, point_y2_read.val });
+        main_trace.push_back(Row{
+            .avm_main_clk = clk,
+            .avm_main_ia = point_x1_read.val,
+            .avm_main_ib = point_y1_read.val,
+            .avm_main_ic = point_x2_read.val,
+            .avm_main_id = point_y2_read.val,
+            .avm_main_internal_return_ptr = FF(internal_return_ptr),
+            .avm_main_mem_idx_a = FF(direct_points_offset + i * 3),
+            .avm_main_mem_idx_b = FF(direct_points_offset + i * 3 + 1),
+            .avm_main_mem_idx_c = FF(direct_points_offset + (i + 1) * 3),
+            .avm_main_mem_idx_d = FF(direct_points_offset + (i + 1) * 3 + 1),
+            .avm_main_mem_op_a = FF(1),
+            .avm_main_mem_op_b = FF(1),
+            .avm_main_mem_op_c = FF(1),
+            .avm_main_mem_op_d = FF(1),
+            .avm_main_pc = FF(pc),
+            .avm_main_r_in_tag = FF(static_cast<uint32_t>(AvmMemoryTag::FF)),
+            .avm_main_tag_err = FF(static_cast<uint32_t>(!tag_match)),
+        });
+        clk++;
+    }
+    // Read the Infinities flags, +4 since we read 4 points row
+    for (uint32_t i = 0; i < num_points; i += 4) {
+        // We can read up to 4 infinities per row
+        // Each infinity flag is separated by 3 memory addressess
+        uint32_t offset = direct_points_offset + i * 3 + 2;
+        auto point_inf1_read = mem_trace_builder.read_and_load_from_memory(
+            call_ptr, clk, IntermRegister::IA, offset, AvmMemoryTag::U8, AvmMemoryTag::U0);
+        offset += 3;
+
+        auto point_inf2_read = mem_trace_builder.read_and_load_from_memory(
+            call_ptr, clk, IntermRegister::IB, offset, AvmMemoryTag::U8, AvmMemoryTag::U0);
+        offset += 3;
+
+        auto point_inf3_read = mem_trace_builder.read_and_load_from_memory(
+            call_ptr, clk, IntermRegister::IC, offset, AvmMemoryTag::U8, AvmMemoryTag::U0);
+        offset += 3;
+
+        auto point_inf4_read = mem_trace_builder.read_and_load_from_memory(
+            call_ptr, clk, IntermRegister::ID, offset, AvmMemoryTag::U8, AvmMemoryTag::U0);
+
+        points_inf_vec.insert(points_inf_vec.end(),
+                              { point_inf1_read.val, point_inf2_read.val, point_inf3_read.val, point_inf4_read.val });
+        bool tag_match = point_inf1_read.tag_match && point_inf2_read.tag_match && point_inf3_read.tag_match &&
+                         point_inf4_read.tag_match;
+        main_trace.push_back(Row{
+            .avm_main_clk = clk,
+            .avm_main_ia = point_inf1_read.val,
+            .avm_main_ib = point_inf2_read.val,
+            .avm_main_ic = point_inf3_read.val,
+            .avm_main_id = point_inf4_read.val,
+            .avm_main_internal_return_ptr = FF(internal_return_ptr),
+            .avm_main_mem_idx_a = FF(direct_points_offset + i * 3 + 2),
+            .avm_main_mem_idx_b = FF(direct_points_offset + (i + 1) * 3 + 2),
+            .avm_main_mem_idx_c = FF(direct_points_offset + (i + 2) * 3 + 2),
+            .avm_main_mem_idx_d = FF(direct_points_offset + (i + 3) * 3 + 2),
+            .avm_main_mem_op_a = FF(1),
+            .avm_main_mem_op_b = FF(1),
+            .avm_main_mem_op_c = FF(1),
+            .avm_main_mem_op_d = FF(1),
+            .avm_main_pc = FF(pc),
+            .avm_main_r_in_tag = FF(static_cast<uint32_t>(AvmMemoryTag::U8)),
+            .avm_main_tag_err = FF(static_cast<uint32_t>(!tag_match)),
+        });
+        clk++;
+    }
+    // Scalar read length is num_points* 2 since scalars are stored as lo and hi limbs
+    uint32_t scalar_read_length = num_points * 2;
+    auto num_scalar_rows = read_slice_to_memory(call_ptr,
+                                                clk,
+                                                direct_scalars_offset,
+                                                AvmMemoryTag::FF,
+                                                AvmMemoryTag::U0,
+                                                FF(internal_return_ptr),
+                                                scalar_read_length,
+                                                scalars_vec);
+    clk += num_scalar_rows;
+    // Reconstruct Grumpkin points
+    std::vector<grumpkin::g1::affine_element> points;
+    for (size_t i = 0; i < num_points; i++) {
+        grumpkin::g1::Fq x = points_coords_vec[i * 2];
+        grumpkin::g1::Fq y = points_coords_vec[i * 2 + 1];
+        bool is_inf = points_inf_vec[i] == 1;
+        if (is_inf) {
+            points.emplace_back(grumpkin::g1::affine_element::infinity());
+        } else {
+            points.emplace_back(x, y);
+        }
+    }
+    // Reconstruct Grumpkin scalars
+    // Scalars are stored as [lo1, hi1, lo2, hi2, ...] with the types [FF, FF, FF, FF, ...]
+    std::vector<grumpkin::fr> scalars;
+    for (size_t i = 0; i < num_points; i++) {
+        FF lo = scalars_vec[i * 2];
+        FF hi = scalars_vec[i * 2 + 1];
+        // hi is shifted 128 bits
+        uint256_t scalar = (uint256_t(hi) << 128) + uint256_t(lo);
+        scalars.emplace_back(scalar);
+    }
+    // Perform the variable MSM - could just put the logic in here since there are no constraints.
+    auto result = ecc_trace_builder.variable_msm(points, scalars, clk);
+    // Write the result back to memory [x, y, inf] with tags [FF, FF, U8]
+    if (indirect_output_flag) {
+        auto read_ind_a =
+            mem_trace_builder.indirect_read_and_load_from_memory(call_ptr, clk, IndirectRegister::IND_A, output_offset);
+        direct_output_offset = uint32_t(read_ind_a.val);
+    }
+    mem_trace_builder.write_into_memory(
+        call_ptr, clk, IntermRegister::IA, direct_output_offset, result.x, AvmMemoryTag::U0, AvmMemoryTag::FF);
+    mem_trace_builder.write_into_memory(
+        call_ptr, clk, IntermRegister::IB, direct_output_offset + 1, result.y, AvmMemoryTag::U0, AvmMemoryTag::FF);
+    main_trace.push_back(Row{
+        .avm_main_clk = clk,
+        .avm_main_ia = result.x,
+        .avm_main_ib = result.y,
+        .avm_main_ind_a = indirect_output_flag ? FF(output_offset) : FF(0),
+        .avm_main_ind_op_a = FF(static_cast<uint32_t>(indirect_output_flag)),
+        .avm_main_internal_return_ptr = FF(internal_return_ptr),
+        .avm_main_mem_idx_a = FF(direct_output_offset),
+        .avm_main_mem_idx_b = FF(direct_output_offset + 1),
+        .avm_main_mem_op_a = FF(1),
+        .avm_main_mem_op_b = FF(1),
+        .avm_main_pc = FF(pc),
+        .avm_main_rwa = FF(1),
+        .avm_main_rwb = FF(1),
+        .avm_main_w_in_tag = FF(static_cast<uint32_t>(AvmMemoryTag::FF)),
+    });
+    clk++;
+    // Write the infinity
+    mem_trace_builder.write_into_memory(call_ptr,
+                                        clk,
+                                        IntermRegister::IA,
+                                        direct_output_offset + 2,
+                                        result.is_point_at_infinity(),
+                                        AvmMemoryTag::U0,
+                                        AvmMemoryTag::U8);
+    main_trace.push_back(Row{
+        .avm_main_clk = clk,
+        .avm_main_ia = static_cast<uint8_t>(result.is_point_at_infinity()),
+        .avm_main_internal_return_ptr = FF(internal_return_ptr),
+        .avm_main_mem_idx_a = FF(direct_output_offset + 2),
+        .avm_main_mem_op_a = FF(1),
+        .avm_main_pc = FF(pc),
+        .avm_main_rwa = FF(1),
+        .avm_main_w_in_tag = FF(static_cast<uint32_t>(AvmMemoryTag::U8)),
+    });
+}
 // Finalise Lookup Counts
 //
 // For log derivative lookups, we require a column that contains the number of times each lookup is consumed

barretenberg/cpp/src/barretenberg/vm/avm_trace/avm_trace.hpp

@@ -204,6 +204,11 @@ class AvmTraceBuilder {
                    uint32_t rhs_y_offset,
                    uint32_t rhs_is_inf_offset,
                    uint32_t output_offset);
+    void op_variable_msm(uint8_t indirect,
+                         uint32_t points_offset,
+                         uint32_t scalars_offset,
+                         uint32_t output_offset,
+                         uint32_t point_length_offset);
 
   private:
     // Used for the standard indirect address resolution of three operands opcode.

barretenberg/cpp/src/barretenberg/vm/avm_trace/gadgets/avm_ecc.cpp

@@ -30,4 +30,21 @@ element AvmEccTraceBuilder::embedded_curve_add(element lhs, element rhs, uint32_
     return result;
 }
 
+element AvmEccTraceBuilder::variable_msm(const std::vector<element>& points,
+                                         const std::vector<grumpkin::fr>& scalars,
+                                         uint32_t clk)
+{
+    // Replace this with pippenger if/when we have the time
+    auto result = grumpkin::g1::affine_point_at_infinity;
+    for (size_t i = 0; i < points.size(); ++i) {
+        result = result + points[i] * scalars[i];
+    }
+
+    std::tuple<FF, FF, bool> result_tuple = { result.x, result.y, result.is_point_at_infinity() };
+
+    ecc_trace.push_back({ .clk = clk, .result = result_tuple });
+
+    return result;
+}
+
 } // namespace bb::avm_trace

barretenberg/cpp/src/barretenberg/vm/avm_trace/gadgets/avm_ecc.hpp

@@ -9,9 +9,9 @@ class AvmEccTraceBuilder {
   public:
     struct EccTraceEntry {
         uint32_t clk = 0;
-        std::tuple<FF, FF, bool> p1; // x, y, is_infinity
-        std::tuple<FF, FF, bool> p2;
-        std::tuple<FF, FF, bool> result;
+        std::tuple<FF, FF, bool> p1 = { FF(0), FF(0), true }; // x, y, is_infinity
+        std::tuple<FF, FF, bool> p2 = { FF(0), FF(0), true };
+        std::tuple<FF, FF, bool> result = { FF(0), FF(0), true };
     };
 
     AvmEccTraceBuilder();
@@ -21,6 +21,9 @@ class AvmEccTraceBuilder {
     grumpkin::g1::affine_element embedded_curve_add(grumpkin::g1::affine_element lhs,
                                                     grumpkin::g1::affine_element rhs,
                                                     uint32_t clk);
+    grumpkin::g1::affine_element variable_msm(const std::vector<grumpkin::g1::affine_element>& points,
+                                              const std::vector<grumpkin::fr>& scalars,
+                                              uint32_t clk);
 
   private:
     std::vector<EccTraceEntry> ecc_trace;