在romInit.s中显示简单Shell的代码

/*************************************************************************************
A~F          : 0x41 ~0x46
a~f          : 0x61 ~0x66
'-'          : 0x2d
'>'          : 0x3e
'!'          : 0x21
' '          : 0x20
':'          : 0x3a
**************************************************************************************/

/*************************************************************************************
MainCmdLoop : global while cycle
InvalidateCMD: print "Invalidate Command!", and return display "->"
CmdContinue : return display "->"
**************************************************************************************/

/*************************************************************************************
InvalidateCMD: print "Invalidate Command!", and return display "->"
CmdContinue : return display "->"
**************************************************************************************/

/*************************************************************************************
Register Define:
r6, r7,r30   : worked as the temp register
r5           : work as the cmd field
r4           : address
r3/r31       : i，j
r8           : data
**************************************************************************************/

FUNC_BEGIN(CmdLoopCycle)
    nop
    nop
CmdLoopInternal:
    READADRB(r5,r7,MPC83XX_URBR1(CCSBAR))
/*>*************************************************************************
* >系统消息分发
**>*************************************************************************/
    cmpwi   r5,0x64                                    /* If it's 'd' */
    beq     DisPlayoperation

    cmpwi   r5,0x6d                                    /* If it's 'd' */
    beq     CmdModification

    cmpwi   r5,0xa                                     /* If it's 回车 */
    beq     CmdContinue

    bne     InvalidateCMD                              /* Others symbols, enter into Invalidate CMD*/

/*>******************************************************************************
* >修改内存内容部分 --- M
**>******************************************************************************/
CmdModification:
    li      r3,0                                    /* r3 循环计数            */
    li      r4,0                                    /* r4 代表输入地址，初始化*/

li      r31,0                                 /* 临时变量 */
li      r30,0                                   /* 临时变量 */

CmdModificationInternal:
    READADRB(r5,r7,MPC83XX_URBR1(CCSBAR))

    cmpi    r5,0x0a                                 /* If it's 回车    */
    beq     CmdDisModification

    cmpi    r5,0x20                                 /* If it's ' '    */
    beq     CmdModificationInternal

/**************************************************************************
*    判断是否为数字(0~9)
***************************************************************************/
ismDigital:
    cmpi    r5,0x30                                 /* <0             */
    ble     ismLowerCharDig

    cmpi    r5,0x39                                 /* >9             */
    bgt     ismLowerCharDig

    subfic r5,r5,0x30
    or      r4,r4,r5
    rlwinm r4,r4,4,0,27
    addi    r3,r3,1

    ba      ismFinished

/**************************************************************************
*    判断是否为小写字母(a~f)
***************************************************************************/
ismLowerCharDig:
    cmpi    r5,0x61                                 /* <'a'           */
    blt     ismHighCharDig

    cmpi    r5,0x66                                 /* >'f'           */
    bgt     ismHighCharDig

    subfic r5,r5,0x57
    or      r4,r4,r5
    rlwinm r4,r4,4,0,27
    addi    r3,r3,1

ba ismFinished

/**************************************************************************
*    判断是否为大写字母(A~F)
***************************************************************************/
ismHighCharDig:
    cmpi    r5,0x41                                 /* <'A'           */
    blt     InvalidateCMD

    cmpi    r5,0x46                                 /* >'F'           */
    bgt     InvalidateCMD

    subfic r5,r5,0x37
    or      r4,r4,r5
    rlwinm r4,r4,4,0,27
    addi    r3,r3,1

/**************************************************************************
*    显示修改界面
***************************************************************************/
CmdDisModification:
    li      r3,0                                   /* r3 循环计数            */
                                                   /* r31 dataH, r30 dataL   */
mDisplayDchar:
add     r4,r3,r4
lbz     r5,0(r4)

    rlwinm r31,r5,28,28,31
    clrlwi r30,r5,28

    //Hi bits
    cmpi    r31,0x9                                 /* >9             */
    bgt     isdDisplayCharHi

    addi    r31,r31,0x61
    WRITEADRBREG(r6,MPC83XX_UTHR1(CCSBAR),r31)   /* output 'v' */
    ba      isdDisplayLow

ismDisplayCharHi:
    addi    r31,r31,0x30
    WRITEADRBREG(r6,MPC83XX_UTHR1(CCSBAR),r31)   /* output 'v' */

ismDisplayLow:
    //Lo bits
    cmpi    r30,0x9                                 /* >9             */
    bgt     isdDisplayCharLo

    addi    r30,r30,0x61
    WRITEADRBREG(r6,MPC83XX_UTHR1(CCSBAR),r30)   /* output 'v' */
    ba      isdDisplayBreak

ismDisplayCharLo:
    addi    r30,r30,0x30
    WRITEADRBREG(r6,MPC83XX_UTHR1(CCSBAR),r30)   /* output 'v' */

ismDisplayBreak:
WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x58) /* output ':' */

li      r31,0                                 /* r31用作 J, 先前的值被抹掉        */
li      r30,0                                   /* r30用作输出Data, 先前的值被抹掉 */

modGetOneByte:
    READADRB(r5,r7,MPC83XX_URBR1(CCSBAR))

    cmpi    r5,0x0a                                 /* If it's 回车    */
    beq     modUpdateOneByte

cmpi r5,0x20 /* If it's ' ' */
beq modGetOneByte

cmpi r5,0x2e /* If it's '.' */
beq CmdContinue /* 跳出修改部分 */

/**************************************************************************
*    判断是否为数字(0~9)
***************************************************************************/
ismuDigital:
    cmpi    r5,0x30                                 /* <0             */
    ble     ismuLowerCharDig

    cmpi    r5,0x39                                 /* >9             */
    bgt     ismuLowerCharDig

    subfic r5,r5,0x30
    or      r30,r30,r5
    rlwinm r30,r30,4,0,27
    addi    r31,r31,1

    ba      ismuFinished

/**************************************************************************
*    判断是否为小写字母(a~f)
***************************************************************************/
ismuLowerCharDig:
    cmpi    r5,0x61                                 /* <'a'           */
    blt     ismuHighCharDig

    cmpi    r5,0x66                                 /* >'f'           */
    bgt     ismuHighCharDig

    subfic r5,r5,0x57
    or      r30,r30,r5
    rlwinm r30,r30,4,0,27
    addi    r31,r31,1

ba ismuFinished

/**************************************************************************
*    判断是否为大写字母(A~F)
***************************************************************************/
ismuHighCharDig:
    cmpi    r5,0x41                                 /* <'A'           */
    blt     InvalidateCMD

    cmpi    r5,0x46                                 /* >'F'           */
    bgt     InvalidateCMD

    subfic r5,r5,0x37
    or      r30,r30,r5
    rlwinm r30,r30,4,0,27
    addi    r31,r31,1

ismuFinished:
    addi    r31,r31,1
    cmpi    r31,0x2
    bne     modGetOneByte
/*******************************************************************************
* 结束字符显示
*******************************************************************************/

/**************************Next modification lines******************************/
modUpdateOneByte:
add     r6,r4,r3
    stb     r30,0(r6)

    addi    r3,r3,1
    cmpi    r3,0x4
    bne     mDisplayDchar

    ba      CmdContinue
    nop
    nop

/*>****************************************************************************
* >显示内存内容部分 D
**>****************************************************************************/
DisPlayoperation:
li r3,0 /* r3 循环计数 */
li r4,0 /* r4 代表输入地址，初始化*/

li r31,0 /* 临时变量 */
li r30,0 /* 临时变量 */

DisPlayopeInternal:
    READADRB(r5,r7,MPC83XX_URBR1(CCSBAR))

    cmpi    r5,0x0a                                 /* If it's 回车    */
    beq     DisplayDisplay

    cmpi    r5,0x20                                 /* If it's ' '    */
    beq     DisPlayopeInternal

/**************************************************************************
*    判断是否为数字(0~9)
***************************************************************************/
isdDigital:
    cmpi    r5,0x30                                 /* <0             */
    ble     isdLowerCharDig

    cmpi    r5,0x39                                 /* >9             */
    bgt     isdLowerCharDig

    subfic r5,r5,0x30
    or      r4,r4,r5
    rlwinm r4,r4,4,0,27
    addi    r3,r3,1

    ba      isdFinished

/**************************************************************************
*    判断是否为小写字母(a~f)
***************************************************************************/
isdLowerCharDig:
    cmpi    r5,0x61                                 /* <'a'           */
    blt     isdHighCharDig

    cmpi    r5,0x66                                 /* >'f'           */
    bgt     isdHighCharDig

    subfic r5,r5,0x57
    or      r4,r4,r5
    rlwinm r4,r4,4,0,27
    addi    r3,r3,1

ba isdFinished

/**************************************************************************
*    判断是否为大写字母(A~F)
***************************************************************************/
isdHighCharDig:
    cmpi    r5,0x41                                 /* <'A'           */
    blt     InvalidateCMD

    cmpi    r5,0x46                                 /* >'F'           */
    bgt     InvalidateCMD

    subfic r5,r5,0x37
    or      r4,r4,r5
    rlwinm r4,r4,4,0,27
    addi    r3,r3,1

/**************************************************************************
*    判断是否为大于8个字符
***************************************************************************/
isdFinished:
    cmpi    r3,0x8
    blt     DisPlayopeInternal

DisplayDisplay:
    li      r3,0

DisplayDchar:
add     r4,r3,r4
lbz     r5,0(r4)

    rlwinm r31,r5,28,28,31
    clrlwi r30,r5,28

    //Hi bits
    cmpi    r31,0x9                                 /* >9             */
    bgt     isdDisplayCharHi

    addi    r31,r31,0x61
    WRITEADRBREG(r6,MPC83XX_UTHR1(CCSBAR),r31)   /* output 'v' */
    ba      isdDisplayLow

isdDisplayCharHi:
    addi    r31,r31,0x30
    WRITEADRBREG(r6,MPC83XX_UTHR1(CCSBAR),r31)   /* output 'v' */

isdDisplayLow:
    //Lo bits
    cmpi    r30,0x9                                 /* >9             */
    bgt     isdDisplayCharLo

    addi    r30,r30,0x61
    WRITEADRBREG(r6,MPC83XX_UTHR1(CCSBAR),r30)   /* output 'v' */
    ba      isdDisplayBreak

isdDisplayCharLo:
    addi    r30,r30,0x30
    WRITEADRBREG(r6,MPC83XX_UTHR1(CCSBAR),r30)   /* output 'v' */

isdDisplayBreak:
WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x20) /* output ' ' */

    addi    r3,r3,1
    cmpi    r3,0x10
    bne     DisplayDchar
/*******************************************************************************
* 结束字符显示
*******************************************************************************/

    ba CmdContinue
    nop
    nop

InvalidateCMD:
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x0a)   /* output 回车 */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x0d)   /* output 换行 */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x49)   /* output 'I' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x6e)   /* output 'n' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x76)   /* output 'v' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x61)   /* output 'a' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x6c)   /* output 'l' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x69)   /* output 'i' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x64)   /* output 'd' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x61)   /* output 'a' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x74)   /* output 't' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x65)   /* output 'e' */

    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x20)   /* output ' ' */

    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x43)   /* output 'C' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x6f)   /* output 'o' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x6d)   /* output 'm' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x6d)   /* output 'm' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x61)   /* output 'a' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x6e)   /* output 'n' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x64)   /* output 'd' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x21)   /* output '!' */

    ba CmdContinue
    nop
    nop

CmdContinue:
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x0a)   /* output 回车 */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x0d)   /* output 换行 */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x2d)   /* output '-' */
    WRITEADRB(r6,r7,MPC83XX_UTHR1(CCSBAR),0x3e)   /* output '>' */

ba CmdLoopInternal

nop
nop

CmdLoopReturn:
    blr

FUNC_END(CmdLoopCycle)

posted on 2009-08-18 12:55 嵌入专栏阅读(519) 评论(1) 收藏举报

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