ra8_freestanding_mem.c File Reference

Project-owned freestanding memory ABI primitives (memset, memcpy, memmove, memcmp, memchr). More...

#include <stddef.h>
#include <stdint.h>
#include "ra8_freestanding.h"

Include dependency graph for ra8_freestanding_mem.c:

Go to the source code of this file.

Functions
void *	memset (void *dst, int value, size_t n)
	Fill memory with a constant byte value.
void *	memcpy (void *dst, const void *src, size_t n)
	Copy memory area between non-overlapping regions.
void *	memmove (void *dst, const void *src, size_t n)
	Copy memory area between potentially overlapping regions.
int	memcmp (const void *a, const void *b, size_t n)
	Compare bytes in two memory areas.
void *	memchr (const void *s, int c, size_t n)
	Locate a byte in a memory area.

Detailed Description

Project-owned freestanding memory ABI primitives (memset, memcpy, memmove, memcmp, memchr).

Tag

[Ring 0 / Foundation] {World: Dual}

Standard ISO C memory primitives implemented directly for the bare-metal RA8 target firmware. Compiled with loop-distribution optimization disabled to guarantee that the compiler never lowers primitive bodies into self-recursive runtime calls. Fully deterministic, bounds-safe, and heap-free.

Copyright

Copyright (c) 2026 Brighton Sikarskie SPDX-License-Identifier: MIT

Since

0.1.0

Definition in file ra8_freestanding_mem.c.

Function Documentation

memchr()

void * memchr	(	const void *	s,
		int	c,
		size_t	n )

Locate a byte in a memory area.

Scans the initial n bytes of s for the first instance of c.

Parameters

[in]	s	Pointer to memory buffer.
[in]	c	Byte value to search for.
[in]	n	Maximum bytes to examine.

Returns

Pointer to matching byte, or nullptr if not found.

Return values

non-null	Pointer to matching byte within s.
nullptr	Byte not found within first n bytes, or n is zero.

Precondition

s points to at least n readable bytes if n > 0.

s is addressable and valid.

Postcondition

Memory buffer is unmodified.

Returned pointer is within [s, s + n) on success.

Note

Freestanding runtime primitive; never allocates; reentrant and thread-safe when memory is not concurrently modified.

Since

0.1.0

Definition at line 164 of file ra8_freestanding_mem.c.

Referenced by elf_string_foreach(), internal_extract_class(), internal_extract_label(), internal_extract_meta(), internal_rtt_match_stage(), internal_scan_tags(), internal_urlname_path_start(), and mdl_extract_hits().

memcmp()

int memcmp	(	const void *	a,
		const void *	b,
		size_t	n )

Compare bytes in two memory areas.

Compares the first n bytes of a and b as unsigned char.

Parameters

[in]	a	First memory area pointer.
[in]	b	Second memory area pointer.
[in]	n	Maximum number of bytes to compare.

Returns

Negative if a < b, positive if a > b, 0 if equal.

Return values

0	All n bytes match or n is zero.
<0	First differing byte in a is less than in b.
>0	First differing byte in a is greater than in b.

Precondition

a points to at least n readable bytes if n > 0.

b points to at least n readable bytes if n > 0.

Postcondition

Input buffers are unmodified.

Comparison semantics follow unsigned byte order.

Note

Freestanding runtime primitive; never allocates; reentrant and thread-safe when memory regions are not concurrently modified.

Since

0.1.0

Definition at line 136 of file ra8_freestanding_mem.c.

Referenced by cdc_echo_round(), demo_read_verify(), demo_restore(), demo_write_verify(), dfu_upload_verify(), er_image_loader(), er_nav_chapter(), fs_fmt_create_and_verify(), fs_fmt_rename_and_verify(), gcm_dec_ok(), gcm_enc_ok(), hid_read_round(), hid_read_round(), internal_attr_duplicate(), internal_bpp(), internal_bytes_equal(), internal_c6_cam_request_is(), internal_cache_decode(), internal_compare(), internal_cookie_field_is(), internal_data_offset(), internal_decode_entity(), internal_demo_read_once(), internal_demo_roundtrip(), internal_demo_roundtrip(), internal_demo_verify_cert_pin(), internal_dispatch(), internal_drive(), internal_end(), internal_format(), internal_is_webp(), internal_is_webp(), internal_jof_is_webp(), internal_kat_one(), internal_key_eq(), internal_mdl_state_decode_header(), internal_mdl_state_scan_slot(), internal_mdl_transfer_commit(), internal_name_chunk(), internal_net_tcp_on_estab(), internal_one_round_trip(), internal_parse_header_region(), internal_probe(), internal_probe_sniff(), internal_program_table(), internal_ra8_io_roundtrip_read_verify(), internal_rtt_drain(), internal_rtt_match_stage(), internal_section_table(), internal_swap_vfs_read_verify(), internal_tc_blob_roundtrip(), internal_upload_verify(), internal_urlname_last_path_marker(), internal_verify_book(), internal_zip_scan_window_for_eocd(), jof_parse(), kat_sha256(), microsd_verify_one(), mlun_verify_one(), ns_host_echo_round(), ospirw_verify_one(), priv_jof_png_prologue(), ra8_io_roundtrip_read_verify(), sdhi_card_block_roundtrip(), sdhi_demo_read_and_verify(), selftest_verify_mram_raw(), selftest_verify_mram_raw(), selftest_verify_mram_raw(), selftest_verify_mram_raw(), selftest_verify_ospi_raw(), sh_paged_hdr_ok(), verify_blob(), wlun_verify_one(), and worker_is_webp().

memcpy()

void * memcpy	(	void *	dst,
		const void *	src,
		size_t	n )

Copy memory area between non-overlapping regions.

Copies n bytes from src to dst sequentially.

Parameters

[out]	dst	Destination buffer pointer.
[in]	src	Source buffer pointer.
[in]	n	Number of bytes to copy.

Returns

Original destination pointer dst.

Return values

dst	The destination pointer passed in dst is always returned.

Precondition

dst and src do not overlap.

dst and src point to at least n valid bytes if n > 0.

Postcondition

The n bytes at dst match the n bytes at src.

Source memory is unmodified.

Note

Freestanding runtime primitive; never allocates; reentrant and thread-safe when memory regions are not concurrently modified.

Since

0.1.0

Definition at line 70 of file ra8_freestanding_mem.c.

Referenced by app_flash_readback(), app_make_cfg(), app_make_manifest(), app_net_read(), board_net_poll_rx(), board_sd_read_block(), board_usb_bridge_bulk_in_take(), board_usb_bridge_bulk_out(), board_usb_bridge_dcp_in_take(), board_usb_bridge_dcp_out(), board_usb_feed_bulk_in(), board_usb_loop_bulk_out(), board_usb_loop_ctrl_out(), board_usbhs_host_shadow_handoff(), board_view_read_rgb888_fd(), book_src_read(), book_src_resident(), cb_host_output_open(), cb_trace_bind(), cm_ct_read(), cm_read(), comic_page_info(), demo_fat_fill_boot(), demo_fat_fill_boot(), demo_fat_fill_root(), demo_fat_fill_root(), demo_fat_fill_sector(), demo_msc_read(), demo_msc_write(), dfu_read(), dfu_write(), emulate_mve(), epub_miniz_realloc(), internal_apply_cookie_line(), internal_arena_realloc(), internal_arena_valid(), internal_authority_of(), internal_backing_read(), internal_bd_copy_slice(), internal_bdsink_fill_chunk(), internal_board_sd_stage_block(), internal_body_buffer_prefix(), internal_book_src_read_paged(), internal_c6_cam_audio_write_header(), internal_c6_get(), internal_c6_output_write(), internal_c6link_op_get_ap(), internal_c6link_op_get_mac(), internal_cache_body_leaf(), internal_cache_copy(), internal_cache_host_leaf(), internal_cache_read_block(), internal_cache_write_block(), internal_cli_artifact_url(), internal_compress_put(), internal_config_set_str(), internal_copy(), internal_copy_fits(), internal_copy_name(), internal_copy_object(), internal_copy_object(), internal_copy_object(), internal_cover_copy(), internal_cursor_entry(), internal_decode_header(), internal_decode_one(), internal_demo_bio_send(), internal_demo_http_get(), internal_demo_roundtrip(), internal_derive_stem(), internal_devcfg_deserialize(), internal_devcfg_serialize(), internal_devcfg_xm_read(), internal_devcfg_xm_write(), internal_dir_next(), internal_dir_pack_sector(), internal_dir_unpack_sector(), internal_download_all(), internal_download_manifest(), internal_drain_rx_slot(), internal_dump_row(), internal_emit(), internal_event_cb(), internal_exfat_list_emit(), internal_fat16_write_bpb(), internal_fat32_write_bpb(), internal_fat_dir_scan_sector(), internal_filter_prefix(), internal_float_to_u32(), internal_flush_band(), internal_h_memcpy(), internal_h_realloc(), internal_handle_init(), internal_hdr_read(), internal_host_echo_send_out(), internal_intern_name(), internal_jof_pull(), internal_json_str(), internal_library_act_on_node(), internal_library_remove_root(), internal_list_pages(), internal_make_header(), internal_make_name(), internal_make_span(), internal_mdl_accept_chunk(), internal_mdl_copy_field(), internal_mdl_http_field_copy(), internal_mdl_stage_headers(), internal_mdl_state_emit_chapters(), internal_mdl_state_encode(), internal_mdl_state_encode_header(), internal_mdl_state_parse_binary64(), internal_mdl_state_paths(), internal_mdl_transfer_commit(), internal_memory_capture(), internal_memory_capture(), internal_memory_read(), internal_memory_write(), internal_meta_candidate_path(), internal_meta_consume(), internal_miss(), internal_mram_read(), internal_mve_mem_exec(), internal_name(), internal_net_eth_hdr(), internal_net_queue(), internal_net_rx_arp(), internal_net_send_arp_reply(), internal_net_send_arp_request(), internal_net_send_tcp(), internal_packet_to_buffer(), internal_packet_to_buffer(), internal_panel_set_name(), internal_parent(), internal_parse_xml_tag(), internal_pax_apply(), internal_pdm_stream_data(), internal_png_consume_rows(), internal_png_translate(), internal_pointer_address(), internal_prof_decimate(), internal_ra8_esp_hosted_c6link_transfer(), internal_ram_read(), internal_ram_write(), internal_ram_write(), internal_ram_write(), internal_rbkc_header(), internal_read_at(), internal_read_block(), internal_render_svg(), internal_resolve_descriptor_path(), internal_resolve_one_leaf(), internal_resolve_path_rel(), internal_resolve_scheme_rel(), internal_sd_boot_frame(), internal_select_window(), internal_slab_next(), internal_slab_set_next(), internal_sort_pages(), internal_spans_overlap(), internal_split_output(), internal_split_output(), internal_split_output(), internal_split_path(), internal_split_path(), internal_stage_name(), internal_str_copy_trimmed(), internal_stub_read(), internal_submit_consume_orphan(), internal_super_read(), internal_swap_rows(), internal_tar_feed(), internal_tar_header(), internal_tar_member(), internal_temp_leaf(), internal_temp_name(), internal_temp_name(), internal_temp_name(), internal_temp_name(), internal_u32_to_float(), internal_urlname_copy(), internal_ustar_name(), internal_vmsc_fill_boot(), internal_vmsc_fill_root(), internal_vmsc_overlay_get(), internal_vmsc_overlay_put(), internal_write_block(), internal_write_entry(), internal_write_eth_header(), internal_write_one_sector(), internal_zip_workspace_realloc(), jof_memstore_pread(), jof_memstore_sink(), main(), mdl_export_workspace_take(), mdl_meta_parse(), mdl_path_join(), mdl_rabook_vfs_validate(), mdl_search_build_url(), mdl_state_set_series_metadata(), mdl_xml_escape(), mg_png_pull(), microsd_msc_read(), mkbookimg_dest_name(), nx_ether_driver_c6_rx(), nx_ether_driver_c6_set_mac(), prep_mailbox(), priv_alphabet_soup_split_path(), priv_bridge_pump_device(), priv_c6link_frame_classify(), priv_c6link_frame_filler(), priv_c6link_frame_seal(), priv_cache_store_super_write(), priv_comic_page_add(), priv_fs_posix_dir_next(), priv_fs_posix_parent_open(), priv_jof_on_rows(), priv_jof_prefix_pull(), priv_mdl_cache_save(), priv_mdl_epub_str_cat(), priv_mdl_export_jof(), priv_mdl_net_curl_buf_write(), priv_mdl_rabook_flat_read(), priv_mdl_state_decimal_to_binary64(), priv_mdl_verify_workspace_take(), priv_media_download_memory_read(), priv_media_download_memory_write_at(), priv_ra8_esp_hosted_rtos_alloc(), priv_ra8_esp_hosted_rtos_block_size(), priv_ra8_esp_hosted_rtos_release(), priv_rar5_filter_delta(), priv_reflow_tok_capture_attr(), priv_rv_trace_reference(), ra8_c6link_mdl_start_request(), ra8_dfu_read_header(), ra8_eth_gwca_default_send(), ra8_eth_gwca_tx_frame(), ra8_img_arena_realloc_sized(), ra8_ota_check_for_update(), ra8_ota_init(), ra8_power_profile_get_stats(), ra8_psa_key_import(), ra8_psa_sign_hash(), ra8_psa_verify_hash(), ra8_rabook_add_image(), ra8_rabook_gray8_encode(), ra8_rabook_intern(), ra8_vmem_stream_read(), ra8_vsource_loader(), rot_tamper_rejected(), sb_tampered_rejected(), selftest_fat_fill_boot(), selftest_fat_fill_boot(), selftest_fat_fill_boot(), selftest_fat_fill_boot(), selftest_fat_fill_boot(), selftest_fat_fill_root(), selftest_fat_fill_root(), selftest_fat_fill_root(), selftest_fat_fill_root(), selftest_fat_fill_root(), selftest_fat_fill_sector(), selftest_fat_fill_sector(), selftest_fat_fill_sector(), selftest_fat_fill_sector(), sh_comic_blob_read(), sh_fit(), sh_paged_mram_read(), sh_reader_render(), sh_shelf_build_thumbs(), strchr(), strrchr(), strstr(), unarch_mem_read(), wlun_msc_read(), wlun_msc_write(), and worker_pull().

memmove()

void * memmove	(	void *	dst,
		const void *	src,
		size_t	n )

Copy memory area between potentially overlapping regions.

Copies n bytes from src to dst handling overlaps safely.

Parameters

[out]	dst	Destination buffer pointer.
[in]	src	Source buffer pointer.
[in]	n	Number of bytes to copy.

Returns

Original destination pointer dst.

Return values

dst	The destination pointer passed in dst is always returned.

Precondition

dst points to at least n writable bytes if n > 0.

src points to at least n readable bytes if n > 0.

Postcondition

The n bytes at dst match the initial n bytes at src.

Handles any overlap between dst and src correctly.

Note

Freestanding runtime primitive; never allocates; reentrant and thread-safe when memory regions are not concurrently modified.

Since

0.1.0

Definition at line 95 of file ra8_freestanding_mem.c.

Referenced by internal_chunk_flat_read(), internal_js_slide(), and internal_prepend_underscore().

memset()

void * memset	(	void *	dst,
		int	value,
		size_t	n )

Fill memory with a constant byte value.

Sets the first n bytes of dst to value converted to uint8_t.

Parameters

[out]	dst	Destination buffer to fill.
[in]	value	Byte value to write.
[in]	n	Number of bytes to write.

Returns

Original destination pointer dst.

Return values

dst	The destination pointer passed in dst is always returned.

Precondition

dst points to at least n writable bytes if n > 0.

The destination memory region is addressable and valid.

Postcondition

The first n bytes of dst contain (uint8_t)value.

Bytes beyond n are unmodified.

Note

Freestanding runtime primitive; never allocates; reentrant and thread-safe when destination memory is not concurrently modified.

Since

0.1.0

Definition at line 45 of file ra8_freestanding_mem.c.

Referenced by app_make_cfg(), app_make_manifest(), ble_npl_callout_init(), ble_npl_event_init(), ble_npl_eventq_init(), board_net_init(), compile_fixture(), demo_calloc(), demo_fat_fill_sector(), demo_jiggle_send(), demo_msc_class_register(), demo_reopen_naive(), epub_entry_open(), fs_fmt_create_and_verify(), fs_fmt_rename_and_verify(), fw_fs_ra8_vfs_init(), fw_fs_space(), fw_fs_stat(), hid_send_iter(), hid_send_iter(), internal_allocate_pipeline(), internal_bdsink_flush(), internal_board_sd_cmd_send_csd(), internal_board_sd_fill_block(), internal_cache_encode_record(), internal_cache_storage(), internal_canfd_reset(), internal_copy_name(), internal_demo_calloc(), internal_demo_get_and_verify(), internal_demo_phase_remount(), internal_demo_put_and_verify(), internal_devcfg_serialize(), internal_dir_pack_sector(), internal_extract_series_metadata(), internal_fill_565(), internal_fill_slot(), internal_fill_strip(), internal_gb_render(), internal_h_calloc(), internal_h_memset(), internal_handle_send(), internal_handle_send(), internal_init_state(), internal_js_begin(), internal_library_workspace_reset(), internal_make_tables(), internal_mdl_next_capacity(), internal_mdl_state_big_init(), internal_mdl_state_big_shift(), internal_mdl_state_encode_header(), internal_mram_reset(), internal_native_window(), internal_net_ip_hdr(), internal_net_send_arp_reply(), internal_net_send_arp_request(), internal_net_send_ping(), internal_net_send_tcp(), internal_png_bind_geometry(), internal_pool_reset(), internal_ra8_io_roundtrip_read_verify(), internal_ram_erase(), internal_rbkc_pack(), internal_read_block(), internal_read_one(), internal_replay_open(), internal_resp_reset(), internal_run_budget(), internal_run_prepared(), internal_sdhi_begin_write(), internal_sdhi_load_block(), internal_sdhi_reset(), internal_seed_cells(), internal_session_mbedtls_setup(), internal_solve_words(), internal_super_read(), internal_swap_vfs_read_verify(), internal_tar_header(), internal_tx_ext_init(), internal_txn_begin(), internal_txn_begin(), internal_validate_body(), internal_vmsc_fill_sector(), internal_wire_window(), internal_write_entry(), internal_xspi_do_erase(), internal_xspi_reset(), load_panel(), long_shift_seam_install(), main(), mdl_extract_hits(), mdl_fetch_run(), mdl_governor_init_clock(), mdl_meta_init(), mdl_rabook_vfs_validate(), mdl_state_add_chapter_numbered(), mdl_state_init(), mem_tile_decode(), microsd_class_register(), mlun_class_register(), ospirw_class_register(), priv_cache_store_super_write(), priv_comic_cbz_open(), priv_dfu_write_secure(), priv_host_deliver_setup(), priv_jof_png_rows(), priv_mdl_export_prepare_cover(), priv_mdl_zip_workspace_bind(), priv_ota_manifest_decode(), priv_ra8_esp_hosted_rtos_deinit(), priv_ra8_esp_hosted_rtos_init(), priv_ra8_esp_hosted_rtos_pool_deinit(), priv_ra8_esp_hosted_rtos_pool_init(), priv_ra8_esp_hosted_rtos_sync_deinit(), priv_ra8_esp_hosted_rtos_sync_init(), priv_viewer_render_jof(), priv_viewer_tile_jof(), ra8_eth_gwca_init_ring(), ra8_eth_gwca_install_linkfix(), ra8_fs_dir_open(), ra8_glyph_atlas_init(), ra8_io_blockdev_vsource_init(), ra8_io_roundtrip_read_verify(), ra8_jpeg_sw_decode(), ra8_jpeg_sw_encode(), ra8_ota_deinit(), ra8_psa_crypto_deinit(), ra8_psa_key_destroy(), ra8_rabook_gray4_downscale(), ra8_rabook_gray4_encode(), ra8_tile_cache_init(), ra8_tls_session_close(), ra8_vmem_init(), ra8_vsource_loader(), ra8_wdt_supervisor_deinit(), ra8_wdt_supervisor_init(), ra8_webp_arena_calloc(), sdhi_card_block_roundtrip(), sdhi_demo_read_and_verify(), sdmsc_class_register(), selftest_fat_fill_sector(), selftest_fat_fill_sector(), selftest_fat_fill_sector(), selftest_fat_fill_sector(), selftest_fat_fill_sector(), selftest_msc_class_register(), selftest_msc_class_register(), selftest_msc_class_register(), soup_init(), and wlun_class_register().