/* Name: usbdrvasm.S
* Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
* Author: Christian Starkjohann
* Creation Date: 2007-06-13
* Tabsize: 4
* Copyright: (c) 2007 by OBJECTIVE DEVELOPMENT Software GmbH
* License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
*/
/*
General Description:
This module is the assembler part of the USB driver. This file contains
general code (preprocessor acrobatics and CRC computation) and then includes
the file appropriate for the given clock rate.
*/
#define __SFR_OFFSET 0 /* used by avr-libc's register definitions */
#include "usbportability.h"
#include "usbdrv.h" /* for common defs */
/* register names */
#ifdef __AVR_ATtiny10__
#define x1 r23
#define x2 r24
#else
#define x1 r16
#define x2 r17
#endif
#define shift r18
#define cnt r19
#define x3 r20
#define x4 r21
#define x5 r22
#define bitcnt x5
#define phase x4
#define leap x4
/* Some assembler dependent definitions and declarations: */
#ifdef __IAR_SYSTEMS_ASM__
extern usbRxBuf, usbDeviceAddr, usbNewDeviceAddr, usbInputBufOffset
extern usbCurrentTok, usbRxLen, usbRxToken, usbTxLen
extern usbTxBuf, usbTxStatus1, usbTxStatus3
# if USB_COUNT_SOF
extern usbSofCount
# endif
public usbCrc16
public usbCrc16Append
COMMON INTVEC
# ifndef USB_INTR_VECTOR
ORG INT0_vect
# else /* USB_INTR_VECTOR */
ORG USB_INTR_VECTOR
# undef USB_INTR_VECTOR
# endif /* USB_INTR_VECTOR */
# define USB_INTR_VECTOR usbInterruptHandler
rjmp USB_INTR_VECTOR
RSEG CODE
#else /* __IAR_SYSTEMS_ASM__ */
# ifndef USB_INTR_VECTOR /* default to hardware interrupt INT0 */
# ifdef INT0_vect
# define USB_INTR_VECTOR INT0_vect // this is the "new" define for the vector
# else
# define USB_INTR_VECTOR SIG_INTERRUPT0 // this is the "old" vector
# endif
# endif
.text
.global USB_INTR_VECTOR
.type USB_INTR_VECTOR, @function
.global usbCrc16
.global usbCrc16Append
#endif /* __IAR_SYSTEMS_ASM__ */
#if USB_INTR_PENDING < 0x40 /* This is an I/O address, use in and out */
# define USB_LOAD_PENDING(reg) in reg, USB_INTR_PENDING
# define USB_STORE_PENDING(reg) out USB_INTR_PENDING, reg
#else /* It's a memory address, use lds and sts */
# define USB_LOAD_PENDING(reg) lds reg, USB_INTR_PENDING
# define USB_STORE_PENDING(reg) sts USB_INTR_PENDING, reg
#endif
#define usbTxLen1 usbTxStatus1
#define usbTxBuf1 (usbTxStatus1 + 1)
#define usbTxLen3 usbTxStatus3
#define usbTxBuf3 (usbTxStatus3 + 1)
;----------------------------------------------------------------------------
; Utility functions
;----------------------------------------------------------------------------
#ifdef __IAR_SYSTEMS_ASM__
/* Register assignments for usbCrc16 on IAR cc */
/* Calling conventions on IAR:
* First parameter passed in r16/r17, second in r18/r19 and so on.
* Callee must preserve r4-r15, r24-r29 (r28/r29 is frame pointer)
* Result is passed in r16/r17
* In case of the "tiny" memory model, pointers are only 8 bit with no
* padding. We therefore pass argument 1 as "16 bit unsigned".
*/
RTMODEL "__rt_version", "3"
/* The line above will generate an error if cc calling conventions change.
* The value "3" above is valid for IAR 4.10B/W32
*/
# define argLen r18 /* argument 2 */
# define argPtrL r16 /* argument 1 */
# define argPtrH r17 /* argument 1 */
# define resCrcL r16 /* result */
# define resCrcH r17 /* result */
# define ptrL ZL
# define ptrH ZH
# define ptr Z
# define byte r22
# define bitCnt r19
# define polyL r20
# define polyH r21
# define scratch r23
#else /* __IAR_SYSTEMS_ASM__ */
/* Register assignments for usbCrc16 on gcc */
/* Calling conventions on gcc:
* First parameter passed in r24/r25, second in r22/23 and so on.
* Callee must preserve r1-r17, r28/r29
* Result is passed in r24/r25
*/
# define argLen r22 /* argument 2 */
# define argPtrL r24 /* argument 1 */
# define argPtrH r25 /* argument 1 */
# define resCrcL r24 /* result */
# define resCrcH r25 /* result */
# define ptrL ZL
# define ptrH ZH
# define ptr z
# define byte r18
#ifdef __AVR_ATtiny10__
# define bitCnt r16
#else
# define bitCnt r19
#endif
# define polyL r20
# define polyH r21
# define scratch r23
#endif
; This implementation is slower, but has less code size
;
; extern unsigned usbCrc16(unsigned char *argPtr, unsigned char argLen);
; argPtr r24+25 / r16+r17
; argLen r22 / r18
; temp variables:
; byte r18 / r22
; bitCnt r19
; poly r20+r21
; scratch r23
; resCrc r24+r25 / r16+r17
; ptr X / Z
usbCrc16Append:
mov ptrL, argPtrL
mov ptrH, argPtrH
ldi resCrcL, 0
ldi resCrcH, 0
ldi polyL, lo8(0xa001)
ldi polyH, hi8(0xa001)
com argLen ; argLen = -argLen - 1: modified loop to ensure that carry is set
ldi bitCnt, 0 ; loop counter with starnd condition = end condition
rjmp usbCrcLoopEntry
usbCrcByteLoop:
ld byte, ptr+
eor resCrcL, byte
usbCrcBitLoop:
ror resCrcH ; carry is always set here (see brcs jumps to here)
ror resCrcL
brcs usbCrcNoXor
eor resCrcL, polyL
eor resCrcH, polyH
usbCrcNoXor:
subi bitCnt, 224 ; (8 * 224) % 256 = 0; this loop iterates 8 times
brcs usbCrcBitLoop
usbCrcLoopEntry:
subi argLen, -1
brcs usbCrcByteLoop
usbCrcReady:
; Thanks to Reimar Doeffinger for optimizing this CRC routine!
; extern unsigned usbCrc16Append(unsigned char *data, unsigned char len);
st ptr+, resCrcL
st ptr+, resCrcH
ret
#undef argLen
#undef argPtrL
#undef argPtrH
#undef resCrcL
#undef resCrcH
#undef ptrL
#undef ptrH
#undef ptr
#undef byte
#undef bitCnt
#undef polyL
#undef polyH
#undef scratch
#if USB_CFG_CHECK_CRC /* separate dispatcher for CRC type modules */
# error "USB_CFG_CLOCK_KHZ is not one of the supported crc-rates!"
#else /* USB_CFG_CHECK_CRC */
# if USB_CFG_CLOCK_KHZ == 12000
# include "usbdrvasm12.inc"
# else
# error "USB_CFG_CLOCK_KHZ is not one of the supported non-crc-rates!"
# endif
#endif /* USB_CFG_CHECK_CRC */
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