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gs_usb: mark all structures as aligned to 4 bytes

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Marking structures as packed as the following 2 results:
- the compiler doesn't insert any holes in the structures
  e.g. if variables are not naturally aligned
- the compiler doesn't assume the base address of the struct to be
  naturally aligned

The 2nd effect results in the compiler (depending on the target
architecture) to generate bad code, as unaligned access is not
possible on all archs.

Mark the structs as aligned to 4 bytes, using the not-so-beautiful
__ALIGN_BEGIN and __ALIGN_END macros.

This saves some bytes and generates probably faster code.

| add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-468 (-468)
| Function                                     old     new   delta
| USBD_GS_CAN_EP0_RxReady                      684     568    -116
| main                                        2712    2360    -352
| Total: Before=17138, After=16670, chg -2.73%
This commit is contained in:
Marc Kleine-Budde 2022-11-11 15:55:34 +01:00
parent f5e5a6e16b
commit 1155a608e0
1 changed files with 12 additions and 11 deletions
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23
include/gs_usb.h
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@ -27,7 +27,8 @@ THE SOFTWARE.
#pragma once
#include <stdint.h>
#include "hal_include.h" //ugly, we just need this for compiler-independant __packed directive ...
#include "compiler.h"
#define u32 uint32_t
#define u8 uint8_t
@ -207,7 +208,7 @@ enum gs_can_termination_state {
/* data types passed between host and device */
struct gs_host_config {
u32 byte_order;
} __packed;
} __packed __aligned(4);
/* The firmware on the original USB2CAN by Geschwister Schneider
* Technologie Entwicklungs- und Vertriebs UG exchanges all data
@ -225,18 +226,18 @@ struct gs_device_config {
u8 icount;
u32 sw_version;
u32 hw_version;
} __packed;
} __packed __aligned(4);
struct gs_device_mode {
u32 mode;
u32 flags;
} __packed;
} __packed __aligned(4);
struct gs_device_state {
u32 state;
u32 rxerr;
u32 txerr;
} __packed;
} __packed __aligned(4);
struct gs_device_bittiming {
u32 prop_seg;
@ -244,7 +245,7 @@ struct gs_device_bittiming {
u32 phase_seg2;
u32 sjw;
u32 brp;
} __packed;
} __packed __aligned(4);
struct gs_device_bt_const {
u32 feature;
@ -257,7 +258,7 @@ struct gs_device_bt_const {
u32 brp_min;
u32 brp_max;
u32 brp_inc;
} __packed;
} __packed __aligned(4);
struct gs_device_bt_const_extended {
u32 feature;
@ -279,11 +280,11 @@ struct gs_device_bt_const_extended {
u32 dbrp_min;
u32 dbrp_max;
u32 dbrp_inc;
} __packed;
} __packed __aligned(4);
struct gs_device_termination_state {
u32 state;
} __packed;
} __packed __aligned(4);
struct gs_host_frame {
u32 echo_id;
@ -298,7 +299,7 @@ struct gs_host_frame {
u32 timestamp_us;
} __packed;
} __packed __aligned(4);
struct gs_host_frame_canfd {
u32 echo_id;
@ -310,4 +311,4 @@ struct gs_host_frame_canfd {
u8 reserved;
u8 data[64];
} __packed;
} __packed __aligned(4);