sha256 support prototype

src/contract_bootloader/execute_syscalls.cairo

@@ -14,6 +14,9 @@ from starkware.cairo.common.registers import get_label_location
 from src.utils.chain_info import chain_id_to_layout
 from src.memorizers.evm.state_access import EvmStateAccess, EvmStateAccessType, EvmDecoderTarget
 from src.utils.chain_info import Layout
+from src.contract_bootloader.sha256_utils import finalize_sha256
+from starkware.cairo.common.alloc import alloc
+from starkware.cairo.common.memcpy import memcpy
 
 struct ExecutionInfo {
     selector: felt,
@@ -28,6 +31,56 @@ struct ExecutionContext {
     execution_info: ExecutionInfo*,
 }
 
+const SHA256_PROCESS_BLOCK_SELECTOR = 'Sha256ProcessBlock';
+
+// Represents 256 bits of a SHA256 state (8 felts each containing 32 bits).
+struct Sha256State {
+    s0: felt,
+    s1: felt,
+    s2: felt,
+    s3: felt,
+    s4: felt,
+    s5: felt,
+    s6: felt,
+    s7: felt,
+}
+
+// Represents 512 bits of a SHA256 input (16 felts each containing 32 bits).
+struct Sha256Input {
+    s0: felt,
+    s1: felt,
+    s2: felt,
+    s3: felt,
+    s4: felt,
+    s5: felt,
+    s6: felt,
+    s7: felt,
+    s8: felt,
+    s9: felt,
+    s10: felt,
+    s11: felt,
+    s12: felt,
+    s13: felt,
+    s14: felt,
+    s15: felt,
+}
+
+struct Sha256ProcessBlock {
+    input: Sha256Input,
+    in_state: Sha256State,
+    out_state: Sha256State,
+}
+
+struct Sha256ProcessBlockRequest {
+    state_ptr: Sha256State*,
+    input_start: Sha256Input*,
+}
+
+struct Sha256ProcessBlockResponse {
+    state_ptr: Sha256State*,
+}
+
+
 // Executes the system calls in syscall_ptr.
 // The signature of the function 'call_execute_syscalls' must match this function's signature.
 //
@@ -53,7 +106,17 @@ func execute_syscalls{
         return ();
     }
 
-    assert [syscall_ptr] = CALL_CONTRACT_SELECTOR;
+    tempvar selector = [syscall_ptr];
+
+    if (selector == SHA256_PROCESS_BLOCK_SELECTOR) {
+        execute_sha256_process_block();
+        return execute_syscalls(
+            execution_context=execution_context, 
+            syscall_ptr_end=syscall_ptr_end
+        );
+    }
+
+    assert selector = CALL_CONTRACT_SELECTOR;
     execute_call_contract(caller_execution_context=execution_context);
 
     return execute_syscalls(execution_context=execution_context, syscall_ptr_end=syscall_ptr_end);
@@ -126,6 +189,50 @@ func execute_call_contract{
     return ();
 }
 
+func execute_sha256_process_block{
+    range_check_ptr,
+    bitwise_ptr: BitwiseBuiltin*,
+    poseidon_ptr: PoseidonBuiltin*,
+    keccak_ptr: KeccakBuiltin*,
+    syscall_ptr: felt*,
+    builtin_ptrs: BuiltinPointers*,
+    pow2_array: felt*,
+    evm_memorizer: DictAccess*,
+    evm_decoder_ptr: felt***,
+    evm_key_hasher_ptr: felt**,
+    starknet_memorizer: DictAccess*,
+    starknet_decoder_ptr: felt***,
+    starknet_key_hasher_ptr: felt**,
+}() {
+    alloc_locals;
+
+    let request_header = cast(syscall_ptr, RequestHeader*);
+    let syscall_ptr = syscall_ptr + RequestHeader.SIZE;
+
+    let request = cast(syscall_ptr, Sha256ProcessBlockRequest*);
+    let syscall_ptr = syscall_ptr + Sha256ProcessBlockRequest.SIZE;
+
+    let response_header = cast(syscall_ptr, ResponseHeader*);
+    let syscall_ptr = syscall_ptr + ResponseHeader.SIZE;
+
+    let response = cast(syscall_ptr, Sha256ProcessBlockResponse*);
+    let syscall_ptr = syscall_ptr + Sha256ProcessBlockResponse.SIZE;
+
+    let (block_ptr_start: felt*) = alloc();
+
+    memcpy(block_ptr_start, request.input_start, Sha256Input.SIZE);    
+    memcpy(block_ptr_start + Sha256Input.SIZE, request.state_ptr, Sha256State.SIZE);
+    memcpy(block_ptr_start + Sha256Input.SIZE + Sha256State.SIZE, response.state_ptr, Sha256State.SIZE);
+
+    let block_ptr_end = block_ptr_start + Sha256Input.SIZE + Sha256State.SIZE + Sha256State.SIZE;
+
+    finalize_sha256(
+        sha256_ptr_start=block_ptr_start, sha256_ptr_end=block_ptr_end
+    );
+
+    return ();
+}
+
 // Returns a failure response with a single felt.
 @known_ap_change
 func write_failure_response{syscall_ptr: felt*}(remaining_gas: felt, failure_felt: felt) {