atmel_sha_fill_padding
atmel_sha_fill_padding(ctx, 64);
atmel_sha_fill_padding(ctx, 128);
atmel_sha_fill_padding(ctx, 0);
atmel_sha_fill_padding(ctx, 0);
atmel_sha_fill_padding(ctx, length);
atmel_sha_fill_padding(ctx, 0);
atmel_sha_fill_padding(ctx, 0);