miscel.inc

一个mp3的解码程序

;Interrupt Control
INTPND	    EQU	0x01e00004
INTMOD	    EQU	0x01e00008
INTMSK	    EQU	0x01e0000c
I_ISPR	    EQU	0x01e00020
I_CMST	    EQU	0x01e0001c

;Watchdog timer
WTCON	    EQU	0x01d30000

;Clock Controller
PLLCON	    EQU	0x01d80000
CLKCON	    EQU	0x01d80004
LOCKTIME    EQU	0x01d8000c 
	
;Memory Controller
REFRESH	    EQU 0x01c80024

;BDMA destination register
BDIDES0     EQU 0x1f80008
BDIDES1     EQU 0x1f80028

;Pre-defined constants
USERMODE    EQU	0x10
FIQMODE	    EQU	0x11
IRQMODE	    EQU	0x12
SVCMODE	    EQU	0x13
ABORTMODE   EQU	0x17
UNDEFMODE   EQU	0x1b
MODEMASK    EQU	0x1f
NOINT	    EQU	0xc0

;PLL constans

M_DIV		EQU	72	;Fin=8MHz Fout=64MHz
P_DIV		EQU	3
S_DIV		EQU	1

_ISR_STARTADDRESS	EQU 0xc7fff00
_VIDEO_ADDRESS      EQU 0xc400000

	MACRO
$HandlerLabel HANDLER $HandleLabel

$HandlerLabel
    sub	    sp,sp,#4	    ;decrement sp(to store jump address)
    stmfd   sp!,{r0}	    ;PUSH the work register to stack(lr does't push because it return to original address)
    ldr	    r0,=$HandleLabel;load the address of HandleXXX to r0
    ldr	    r0,[r0]	    	;load the contents(service routine start address) of HandleXXX
    str	    r0,[sp,#4]	    ;store the contents(ISR) of HandleXXX to stack
    ldmfd   sp!,{r0,pc}	    ;POP the work register and pc(jump to ISR)
    MEND
    
    END