165 lines
6.2 KiB
ArmAsm
165 lines
6.2 KiB
ArmAsm
/****************************************************************
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KPIT Cummins Infosystems Ltd, Pune, India.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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*****************************************************************/
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/* Start-up code for M16C targets only */
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.text
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.global _start
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.type _start, @function
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_start:
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ldc #_istack, isp /* set interrupt stack pointer */
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#ifndef EXT_RAM
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mov.b #0x02,0x0a /* write enable in protect register */
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mov.b #0x00,0x04 /* set processer mode :single chip mode */
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/* 0x04 is the address of processor mode register 0 */
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mov.b #0x00,0x0a /* write disable in protect register */
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#endif
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#if EXT_RAM
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mov.w #0x000a,a0 /* Write enable in protect register */
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mov.b #0xff,[a0]
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mov.w #0x04,a0 /* Memory expansion mode, WRH/WRL/RD signals */
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mov.b #0x05,[a0]
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mov.w #0x05,a0 /* Insert wait, no limit in on-chip memory */
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mov.b #0x88,[a0]
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mov.w #0x08,a0 /* Enable all the CS signals with wait */
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mov.b #0x0F,[a0]
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mov.w #0x0a,a0 /* write disable in protect register */
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mov.b #0x00,[a0]
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#endif
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; ldc #0x0080,flg /* select USER STACK POINTER (BIT7=1,USP) (BIT7=0,ISP) */
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; ldc #_ustack,sp /* set user stack pointer */
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/* INTERRUPT VECTOR ADDRESS definition */
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ldc #0xF, intbh /* load upper 4 bits of variable vector address in intbh */
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ldc #0xA000, intbl /* load lower 16 bits of variable vector address in intbl */
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fset I /* ADD THIS TO ENABLE INTERRUPTS */
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/* call the hardware initialiser */
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; jsr.a _hw_initialise
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/* load data section from ROM to RAM */
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mov.b #%hi8(_mdata),r1h /* move upper 4 bits of the 20 bit address (_mdata) to, r1h */
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mov.w #%lo16(_mdata),a0 /* move lower 16 bits of the 20 bit address (_mdata) to,a0 */
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mov.w #_data,a1 /* store the start address of data section in, A1 */
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mov.w #_edata,r3 /* store the end address of data section in R3 */
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sub.w a1,r3 /* R3=R3-A1. Store size of data section in R3 */
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mov.w r3,r2 /* Store size of data section in R2 */
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smovf.b
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/* bss initialisation : zero out bss */
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mov.b #0x00,R0L /* load R0L reg with 0x0 (value at which bss section will be initialised) */
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mov.w #_bss, a1 /* store the start address of bss in A1 */
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mov.w #_ebss, a0 /* store the end address of bss in A0 */
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sub.w a1,a0 /* (A0 = A0-A1) */
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mov.w a0,r3 /* Store size of bss section in reg R3 */
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sstr.b
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#if EXT_RAM
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/* load fdata section from ROM to External RAM only if EXT_RAM is defined */
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pushc sp /*store stack pointer in stack */
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popc fb /*copy the stack pointer in frame base register */
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push.w #%hi16(_mdata) /* offset of -2 from fb: store higher 16 bits of _mdata */
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push.w #%lo16(_mdata) /* offset of -4 from fb: store lower 16 bits of _mdata */
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mov.w #_edata,r0 /* end address of data section */
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mov.w #_data,r1 /* start address of data section */
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sub.w r1,r0 /* size of data section in r0 */
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add.w r0,-4[fb] /* store the lower 16 bits of source address on stack */
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adc.w #0,-2[fb] /* store the higher 4 bits of source address on stack */
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push.w #%hi16(_fdata) /* offset -6 from fp: store the higher 4 bits of destination address on stack */
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push.w #%lo16(_fdata) /* offset -8 from fp: store the lower 16 bits of destination address on stack */
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push.w #%hi16(_efdata) /* offset -10 from fp: higher 16 bits of _efdata */
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push.w #%lo16(_efdata) /* offset -12 from fp: lower 16 bits of _efdata */
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label1:
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cmp.w -6[fb],-10[fb] /* Compare higher 16 bits of _fdata and _efdata */
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jnz label2
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cmp.w -8[fb],-12[fb] /* Compare lower 16 bits of _fdata and _efdata */
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jeq init_fdata_end
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label2:
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mov.w -2[fb],a1 /* Copy higher 16 bits of source in A1 */
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mov.w -4[fb],a0 /* Copy lower 16 bits of source in A1 */
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lde.b [a1a0],r0l /* Copy contents of a1a0 in r0l */
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mov.w -6[fb],a1 /* Copy higher 16 bits of destination in A1 */
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mov.w -8[fb],a0 /* Copy lower 16 bits of destination in A0 */
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ste.b r0l,[a1a0] /* store r0l contents at [a1a0] */
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add.w #0x01,-4[fb] /* increment lower 16 bits of source */
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adcf.w -2[fb] /* add carry to higher 16 bits of source */
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add.w #0x01,-8[fb] /* increment lower 16 bits of destination */
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adcf.w -6[fb] /* add carry to higher 16 bits of destination */
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jmp.b label1
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init_fdata_end:
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pop.w r0 /* clean stack */
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pop.w r0
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pop.w r0
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pop.w r0
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pop.w r0
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pop.w r0
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/* Zero out fbss section */
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push.w #%hi16(_fbss) /* offset of -2 from fb: higher 16 bits of _fbss */
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push.w #%lo16(_fbss) /* offset of -4 from fb: lower 16 bits of _fbss */
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push.w #%hi16(_efbss) /* offset of -6 from fb: higer 16 bits of _efbss */
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push.w #%lo16(_efbss) /* offset of -8 from fb: lower 16 bits of _efbss */
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mov.b #0x00,r0l
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label3:
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cmp.w -2[fb],-6[fb] /* Compare higher 16 bits of _fdata and _efdata */
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jnz label4
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cmp.w -4[fb],-8[fb] /* Compare lower 16 bits of _fdata and _efdata */
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jeq init_fbss_end
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label4:
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mov.w -2[fb],a1 /* Copy higher 16 bits of source in A1 */
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mov.w -4[fb],a0 /* Copy lower 16 bits of source in A1 */
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ste.b r0l,[a1a0] /* store r0l contents at [a1a0] */
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add.w #0x01,-4[fb] /* increment lower 16 bits of _fbss */
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adcf.w -2[fb] /* add carry to higher 16 bits of _fbss */
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jmp.b label3
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init_fbss_end:
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pop.w r0 /* clean stack */
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pop.w r0
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pop.w r0
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pop.w r0
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#endif
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/* start user program */
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jsr.a _main
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.end
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