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;/*****************************************************************************/ 
;/* SWI.S: SWI Handler                                                        */ 
;/*****************************************************************************/ 
;/* This file is part of the uVision/ARM development tools.                   */ 
;/* Copyright (c) 2005-2006 Keil Software. All rights reserved.               */ 
;/* This software may only be used under the terms of a valid, current,       */ 
;/* end user licence from KEIL for a compatible version of KEIL software      */ 
;/* development tools. Nothing else gives you the right to use this software. */ 
;/*****************************************************************************/ 
 
T_Bit           EQU     0x20 
 
                PRESERVE8                      ; 8-Byte aligned Stack 
                AREA    SWI_Area, CODE, READONLY 
                ARM 
 
                EXPORT  SWI_Handler 
SWI_Handler    
 
                STMFD   SP!, {R12, LR}         ; Store R12, LR 
                MRS     R12, SPSR              ; Get SPSR 
                STMFD   SP!, {R8, R12}         ; Store R8, SPSR 
                TST     R12, #T_Bit            ; Check Thumb Bit 
                LDRNEH  R12, [LR,#-2]          ; Thumb: Load Halfword 
                BICNE   R12, R12, #0xFF00      ;        Extract SWI Number 
                LDREQ   R12, [LR,#-4]          ; ARM:   Load Word 
                BICEQ   R12, R12, #0xFF000000  ;        Extract SWI Number 
 
                LDR     R8, SWI_Count 
                CMP     R12, R8 
                BHS     SWI_Dead               ; Overflow 
                ADR     R8, SWI_Table 
                LDR     R12, [R8,R12,LSL #2]   ; Load SWI Function Address 
                MOV     LR, PC                 ; Return Address 
                BX      R12                    ; Call SWI Function  
 
                LDMFD   SP!, {R8, R12}         ; Load R8, SPSR 
;               MSR     SPSR_cxsf, R12         ; Set SPSR 
                LDMFD   SP!, {R12, PC}^        ; Restore R12 and Return 
 
SWI_Dead        B       SWI_Dead               ; None Existing SWI 
 
SWI_Cnt         EQU    (SWI_End-SWI_Table)/4 
SWI_Count       DCD     SWI_Cnt 
 
                IMPORT  __SWI_0 
                IMPORT  __SWI_1 
SWI_Table 
                DCD     __SWI_0                ; SWI 0 Function Entry 
                DCD     __SWI_1                ; SWI 1 Function Entry 
SWI_End 
 
 
                END