/* Name: usbdrvasm.S * Project: AVR USB driver * 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) or proprietary (CommercialLicense.txt) * Revision: $Id$ *//*General Description:This module is the assembler part of the USB driver. This file containsgeneral code (preprocessor acrobatics and CRC computation) and then includesthe file appropriate for the given clock rate.*/#include "iarcompat.h"#ifndef __IAR_SYSTEMS_ASM__    /* configs for io.h */#   define __SFR_OFFSET 0#   define _VECTOR(N)   __vector_ ## N   /* io.h does not define this for asm */#   include <avr/io.h> /* for CPU I/O register definitions and vectors */#endif  /* __IAR_SYSTEMS_ASM__ */#include "usbdrv.h" /* for common defs *//* register names */#define x1      r16#define x2      r17#define shift   r18#define cnt     r19#define x3      r20#define x4      r21#define bitcnt  r22#define phase   x4#define leap    x4/* Some assembler dependent definitions and declarations: */#ifdef __IAR_SYSTEMS_ASM__#   define nop2     rjmp    $+2 /* jump to next instruction */#   define XL       r26#   define XH       r27#   define YL       r28#   define YH       r29#   define ZL       r30#   define ZH       r31#   define lo8(x)   LOW(x)#   define hi8(x)   ((x)>>8)    /* not HIGH to allow XLINK to make a proper range check */    extern  usbRxBuf, usbDeviceAddr, usbNewDeviceAddr, usbInputBufOffset    extern  usbCurrentTok, usbRxLen, usbRxToken, usbTxLen    extern  usbTxBuf, usbMsgLen, usbTxLen1, usbTxBuf1, usbTxLen3, usbTxBuf3    public  usbCrc16    public  usbCrc16Append    COMMON  INTVEC    ORG     INT0_vect    rjmp    SIG_INTERRUPT0    RSEG    CODE#else /* __IAR_SYSTEMS_ASM__ */#   define nop2     rjmp    .+0 /* jump to next instruction */    .text    .global SIG_INTERRUPT0    .type   SIG_INTERRUPT0, @function    .global usbCrc16    .global usbCrc16Append#endif /* __IAR_SYSTEMS_ASM__ */;----------------------------------------------------------------------------; 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     XL#   define ptrH     XH#   define ptr      x#   define byte     r18#   define bitCnt   r19#   define polyL    r20#   define polyH    r21#   define scratch  r23#endif; extern unsigned usbCrc16(unsigned char *data, unsigned char len);; data: r24/25; len: r22; temp variables:;   r18: data byte;   r19: bit counter;   r20/21: polynomial;   r23: scratch;   r24/25: crc-sum;   r26/27=X: ptrusbCrc16:    mov     ptrL, argPtrL    mov     ptrH, argPtrH    ldi     resCrcL, 0xff    ldi     resCrcH, 0xff    ldi     polyL, lo8(0xa001)    ldi     polyH, hi8(0xa001)crcByteLoop:    subi    argLen, 1    brcs    crcReady    ld      byte, ptr+    ldi     bitCnt, 8crcBitLoop:    mov     scratch, byte    eor     scratch, resCrcL    lsr     resCrcH    ror     resCrcL    lsr     byte    sbrs    scratch, 0    rjmp    crcNoXor    eor     resCrcL, polyL    eor     resCrcH, polyHcrcNoXor:    dec     bitCnt    brne    crcBitLoop    rjmp    crcByteLoopcrcReady:    com     resCrcL    com     resCrcH    ret; extern unsigned usbCrc16Append(unsigned char *data, unsigned char len);usbCrc16Append:    rcall   usbCrc16    st      ptr+, resCrcL    st      ptr+, resCrcH    ret;----------------------------------------------------------------------------; Now include the clock rate specific code;----------------------------------------------------------------------------#ifndef USB_CFG_CLOCK_KHZ#   define USB_CFG_CLOCK_KHZ 12000#endif#if USB_CFG_CLOCK_KHZ == 12000#   include "usbdrvasm12.S"#elif USB_CFG_CLOCK_KHZ == 16000#   include "usbdrvasm16.S"#elif USB_CFG_CLOCK_KHZ == 16500#   include "usbdrvasm165.S"#else#   error "USB_CFG_CLOCK_KHZ is not one of the supported rates!"#endif