// ════════════════════════════════════════════════════════════════
// SOV_CONTROL.CMM — Sovereign APL State Machine
// C-- control flow for multi-step density matrix evolution
// Compiled: c-- -> LLVM IR -> MLIR -> Machine Code
// No prologue/epilogue overhead. Hand-tuned register layout.
// ════════════════════════════════════════════════════════════════

section "text" {

  // sov_apl_evolve_cmm
  // Args (System V AMD64 ABI):
  //   R0 = H_ptr          (complex(dp) column-major, n x n)
  //   R1 = rho_ptr        (complex(dp) column-major, n x n, in/out)
  //   R2 = n              (int64)
  //   R3 = steps          (int64)
  //   R4 = dt             (float64, via xmm0 on x86_64)
  //   R5 = sk_ptr         (Ed25519 secret key, 32 bytes)
  //   R6 = pk_ptr         (Ed25519 public key, 32 bytes)
  //   R7 = receipts_ptr   (uint8_t[steps * 96])
  // Returns: rax = 0 (ok) | error code

  export sov_apl_evolve_cmm;

  sov_apl_evolve_cmm
    ( bits64 H_ptr, bits64 rho_ptr, bits64 n, bits64 steps,
      bits64 dt, bits64 sk_ptr, bits64 pk_ptr, bits64 receipts_ptr )
    {
      bits64 step, receipt_off, hash_ptr, sig_ptr;
      bits64 RECEIPT_SZ = 96;  // HASH_LEN(32) + SIG_LEN(64)

      // Step counter
      step = 0;

    L_check:
      if step >= steps goto L_done;

      // Compute receipt buffer offset for this step
      receipt_off = step * RECEIPT_SZ;
      hash_ptr    = receipts_ptr + receipt_off;
      sig_ptr     = receipts_ptr + receipt_off + 32;

      // Call Fortran kernel: sov_apl_step_zgemm_fused
      foreign "C" sov_apl_step_zgemm_fused
        ( H_ptr, n, rho_ptr, n, dt, sk_ptr, pk_ptr,
          rho_ptr, hash_ptr, sig_ptr );

      // Advance
      step = step + 1;
      goto L_check;

    L_done:
      return ( 0::bits64 );

    // Fault path: minimal — write code, halt
    L_fault:
      bits64 fault_mem = 0x0000DEAD0000;
      W_ [fault_mem] = step;
      call "asm" { "hlt" };
    }

  // sov_verify_receipt
  // Verifies a single receipt (hash || sig) for a given rho snapshot
  // Returns 1 if valid, 0 if tampered
  export sov_verify_receipt;

  sov_verify_receipt
    ( bits64 rho_ptr, bits64 n, bits64 receipt_ptr, bits64 pk_ptr )
    {
      bits64 hash_ptr, sig_ptr, ok;

      hash_ptr = receipt_ptr;        // first 32 bytes
      sig_ptr  = receipt_ptr + 32;   // next 64 bytes

      // Call Fortran: sov_bifrost_verify
      ok = foreign "C" sov_bifrost_verify
        ( hash_ptr, 32, sig_ptr, pk_ptr );

      return ( ok );
    }

} // section "text"