/*===============================================================*\ | Project: RTEMS generic MPC5200 BSP | +-----------------------------------------------------------------+ | Partially based on the code references which are named below. | | Adaptions, modifications, enhancements and any recent parts of | | the code are: | | Copyright (c) 2005 | | Embedded Brains GmbH | | Obere Lagerstr. 30 | | D-82178 Puchheim | | Germany | | rtems@embedded-brains.de | +-----------------------------------------------------------------+ | The license and distribution terms for this file may be | | found in the file LICENSE in this distribution or at | | | | http://www.rtems.com/license/LICENSE. | | | +-----------------------------------------------------------------+ | this file contains the startup assembly code | \*===============================================================*/ /***********************************************************************/ /* */ /* Module: start.S */ /* Date: 07/17/2003 */ /* Purpose: RTEMS MPC5x00 CPU assembly startup */ /* */ /*---------------------------------------------------------------------*/ /* */ /* Description: This file contains the assembler portion of MPC5x00 */ /* startup code */ /* */ /*---------------------------------------------------------------------*/ /* */ /* Code */ /* References: startup code for Motorola PQII ADS board */ /* Module: start.S */ /* Project: RTEMS 4.6.0pre1 / MCF8260ads BSP */ /* Version 1.2 */ /* Date: 04/18/2002 */ /* */ /* Author(s) / Copyright(s): */ /* */ /* Modified for the Motorola PQII ADS board by */ /* Andy Dachs 23-11-00. */ /* Surrey Satellite Technology Limited */ /* */ /* I have a proprietary bootloader programmed into the flash */ /* on the board which initialises the SDRAM prior to calling */ /* this function. */ /* */ /* This file is based on the one by Jay Monkman (jmonkman@fracsa.com)*/ /* which in turn was based on the dlentry.s file for the Papyrus BSP,*/ /* written by: */ /* */ /* Author: Andrew Bray */ /* */ /* COPYRIGHT (c) 1995 by i-cubed ltd. */ /* */ /* To anyone who acknowledges that this file is provided "AS IS" */ /* without any express or implied warranty: */ /* permission to use, copy, modify, and distribute this file */ /* for any purpose is hereby granted without fee, provided that */ /* the above copyright notice and this notice appears in all */ /* copies, and that the name of i-cubed limited not be used in */ /* advertising or publicity pertaining to distribution of the */ /* software without specific, written prior permission. */ /* i-cubed limited makes no representations about the suitability */ /* of this software for any purpose. */ /* */ /*---------------------------------------------------------------------*/ /* */ /* Partially based on the code references which are named above. */ /* Adaptions, modifications, enhancements and any recent parts of */ /* the code are under the right of */ /* */ /* IPR Engineering, Dachauer Straße 38, D-80335 München */ /* Copyright(C) 2003 */ /* */ /*---------------------------------------------------------------------*/ /* */ /* IPR Engineering makes no representation or warranties with */ /* respect to the performance of this computer program, and */ /* specifically disclaims any responsibility for any damages, */ /* special or consequential, connected with the use of this program. */ /* */ /*---------------------------------------------------------------------*/ /* */ /* Version history: 1.0 */ /* */ /***********************************************************************/ #include #include #include #include "../include/mpc5200.h" #include "../include/bsp.h" /* Macro definitions to load a register with a 32-bit address. Both functions identically. Sometimes one mnemonic is more appropriate than the other. reg -> register to load value -> value to be loaded LA reg,value ("Load Address") LWI reg,value ("Load Word Immediate") */ .macro LA reg, value lis \reg , \value@h ori \reg , \reg, \value@l sync .endm .macro LWI reg, value lis \reg , (\value)@h ori \reg , \reg, (\value)@l sync .endm /* Macro definitions to test, set or clear a single bit or bit pattern in a given 32bit GPR. reg1 -> register content to be tested reg2 -> 2nd register only needed for computation mask -> any bit pattern */ .macro TSTBITS reg1, reg2, mask /* Match is indicated by EQ=0 (CR) */ LWI \reg2, \mask /* Unmatch is indicated by EQ=1 (CR) */ and \reg1, \reg1, \reg2 cmplw \reg1, \reg2 sync .endm .macro SETBITS reg1, reg2, mask LWI \reg2, \mask or \reg1, \reg1, \reg2 sync .endm .macro CLRBITS reg1, reg2, mask LWI \reg2, \mask andc \reg1, \reg1, \reg2 sync .endm /* Some register offsets of MPC5x00 memory map registers */ .set CS0STR, 0x04 .set CS0STP, 0x08 .set CS1STR, 0x0C .set CS1STP, 0x10 .set SDRAMCS0, 0x34 .set SDRAMCS1, 0x38 .set BOOTSTR, 0x4C .set BOOTSTP, 0x50 .set ADREN, 0x54 .set CSSR0, 0x58 /* Critical Interrupt SSR0 (603le only) */ .set CSSR1, 0x59 /* Critical Interrupt SSR1 (603le only) */ .set CFG, 0x20C .set CSBOOTROM, 0x300 .set CSCONTROL, 0x318 .set CS1CONF, 0x304 /* Register offsets of MPC5x00 SDRAM memory controller registers */ .set MOD, 0x100 .set CTRL, 0x104 .set CFG1, 0x108 .set CFG2, 0x10C .set ADRSEL, 0x110 /* Register offsets of MPC5x00 GPIO registers needed */ .set GPIOPCR, 0xb00 .set GPIOWE, 0xc00 .set GPIOWOD, 0xc04 .set GPIOWDD, 0xc08 .set GPIOWDO, 0xc0c .set GPIOSEN, 0xb04 .set GPIOSDD, 0xb0c .set GPIOSDO, 0xb10 /* Register offsets of MPC5x00 Arbiter registers */ .set ARBCFG, 0x1f40 .set ARBMPREN, 0x1f64 .set ARBMPRIO, 0x1f68 .set ARBSNOOP, 0x1f70 /* Some bit encodings for MGT5100 registers */ .set ADREN_SDRAM_EN, (1<<22) .set ADREN_BOOT_EN, (1<<25) .set ADREN_CS0_EN, (1<<16) .set ADREN_CS1_EN, (1<<17) .set CTRL_PRECHARGE, (1<<1) .set CTRL_REFRESH, (1<<2) .set CTRL_BA1, (1<<31) .set CSCONF_CE, (1<<12) /* Some fixed values for MPC5x00 registers */ .set CSBOOTROM_VAL, 0x0101D910 .set CSCONTROL_VAL, 0x91000000 .set CFG_VAL, 0x00000100 .extern _bss_start .extern _bss_size .extern _data_start .extern _data_size .extern _text_start .extern _text_size /*.extern _s_got*/ .extern boot_card .extern MBAR .section ".entry" PUBLIC_VAR (start) start: /* 1st: initialization work (common for RAM/ROM startup) */ mfmsr r30 SETBITS r30, r29, MSR_ME|MSR_RI CLRBITS r30, r29, MSR_EE mtmsr r30 /* Set RI/ME, Clr EE in MSR */ #if defined(HAS_UBOOT) /* store pointer to UBoot bd_info board info structure */ LWI r31,uboot_bdinfo_ptr stw r3,0(r31) #endif /* defined(HAS_UBOOT) */ #if defined(NEED_LOW_LEVEL_INIT) /* initialize the MBAR (common RAM/ROM startup) */ LWI r31, MBAR_RESET LWI r29, MBAR rlwinm r30, r29,16,16,31 stw r30, 0(r31) /* Set the MBAR */ #endif LWI r31, MBAR /* set r31 to current MBAR */ /* init GPIOPCR */ lwz r29,GPIOPCR(r31) LWI r30, GPIOPCR_INITMASK not r30,r30 and r29,r29,r30 LWI r30, GPIOPCR_INITVAL or r29,r29,r30 stw r29, GPIOPCR(r31) /* further initialization work (common RAM/ROM startup) */ bl TLB_init /* Initialize TLBs */ bl FID_DCache /* Flush, inhibit and disable data cache */ bl IDUL_ICache /* Inhibit, disable and unlock instruction cache */ bl FPU_init /* Initialize FPU */ #if defined(NEED_LOW_LEVEL_INIT) bl SPRG_init /* Initialize special purpose registers */ #endif #if defined(NEED_LOW_LEVEL_INIT) /* detect RAM/ROM startup (common for RAM/ROM startup) */ LWI r20, ROM_START /* set the relocation offset */ LWI r30, CFG_VAL /* get CFG register content */ lwz r30, CFG(r31) /* set SDRAM single data rate / XLB_CLK=FVCO/4 / IPB_CLK=XLB_CLK/2 / PCICLK=IPB_CLK */ lwz r30, ADREN(r31) /* get content of ADREN */ TSTBITS r30, r29, ADREN_BOOT_EN bne skip_ROM_start /* If BOOT_ROM is not enabled, skip further initialization */ /* do some board dependent configuration (unique for ROM startup) */ bl SPRG_brk_init /* Initialize special purpose onchip breakpoint registers */ LWI r30, CSCONTROL_VAL /* get CSCONTROL register content */ stw r30, CSCONTROL(r31) /* enable internal/external bus error and master for CS */ #ifdef BRS5L LWI r30, CSBOOTROM_VAL stw r30, CSBOOTROM(r31) /* Set CSBOOTROM */ #endif /* FIXME: map BOOT ROM into final location with CS0 registers */ LWI r30, ROM_START rlwinm r30, r30,17,15,31 stw r30, CS0STR(r31) /* Set CS0STR */ lis r30, ROM_END@h ori r30, r30, ROM_END@l rlwinm r30, r30,17,15,31 stw r30, CS0STP(r31) /* Set CS0STP */ lwz r30, ADREN(r31) /* get content of ADREN */ SETBITS r30, r29, ADREN_CS0_EN stw r30, ADREN(r31) /* enable CS0 mapping */ isync /* jump to same code in final BOOT ROM location */ LWI r30, reloc_in_CS0 LWI r29, RAM_START sub r30,r30,r29 LWI r29, ROM_START add r30,r30,r29 mtctr r30 bctr reloc_in_CS0: /* disable CSBOOT (or map it to CS0 range) */ lwz r30, ADREN(r31) /* get content of ADREN */ CLRBITS r30, r29, ADREN_BOOT_EN stw r30, ADREN(r31) /* disable BOOT mapping */ /* init SDRAM */ LWI r30, RAM_START ori r30,r30,0x1a /* size code: bank is 128MByte */ stw r30,SDRAMCS0(r31) /* Set SDRAMCS0 */ LWI r30,(RAM_SIZE)>>1 ori r30,r30,0x1a /* size code: bank is 128MByte */ stw r30, SDRAMCS1(r31) /* Set SDRAMCS1 */ bl SDRAM_init /* Initialize SDRAM controller */ /* init arbiter and stuff... */ LWI r30, 0x8000a06e stw r30, ARBCFG(r31) /* Set ARBCFG */ LWI r30, 0x000000ff stw r30, ARBMPREN(r31) /* Set ARBMPREN */ LWI r30, 0x00001234 stw r30, ARBMPRIO(r31) /* Set ARBPRIO */ LWI r30, 0x0000001e stw r30, ARBSNOOP(r31) /* Set ARBSNOOP */ /* copy .text section from ROM to RAM location (unique for ROM startup) */ LA r30, _text_start /* get start address of text section in RAM */ add r30, r20, r30 /* get start address of text section in ROM (add reloc offset) */ LA r29, _text_start /* get start address of text section in RAM */ LA r28, _text_size /* get size of RAM image */ bl copy_image /* copy text section from ROM to RAM location */ /* copy .data section from ROM to RAM location (unique for ROM startup) */ LA r30, _data_start /* get start address of data section in RAM */ add r30, r20, r30 /* get start address of data section in ROM (add reloc offset) */ LA r29, _data_start /* get start address of data section in RAM */ LA r28, _data_size /* get size of RAM image */ bl copy_image /* copy initialized data section from ROM to RAM location */ LA r29, remap_rom /* get compile time address of label */ mtlr r29 blrl /* now further execution RAM */ remap_rom: /* remap BOOT ROM to CS0 (common for RAM/ROM startup) */ lwz r30, CSBOOTROM(r31) /* get content of CSBOOTROM */ CLRBITS r30, r29, CSCONF_CE stw r30, CSBOOTROM(r31) /* disable BOOT CS */ lwz r30, ADREN(r31) /* get content of ADREN */ mr r29, r30 /* move content of r30 to r29 */ LWI r30, ADREN_BOOT_EN /* mask ADREN_BOOT_EN */ andc r29,r29,r30 LWI r30, ADREN_CS0_EN /* unmask ADREN_CS0_EN */ or r29,r29,r30 stw r29,ADREN(r31) /* Simultaneous enable CS0 and disable BOOT address space */ lwz r30, CSBOOTROM(r31) /* get content of CSBOOTROM */ SETBITS r30, r29, CSCONF_CE stw r30, CSBOOTROM(r31) /* disable BOOT CS */ skip_ROM_start: /* configure external DPRAM CS1 */ LWI r30,0xFFFFFB10 stw r30,CS1CONF(r31) /* map external DPRAM (CS1) */ LWI r30,(DPRAM_START>>16) stw r30,CS1STR(r31) LWI r30,((DPRAM_END)>>16) stw r30,CS1STP(r31) lwz r30, ADREN(r31) /* get content of ADREN */ LWI r29, ADREN_CS1_EN /* unmask ADREN_CS1_EN */ or r30,r30,r29 stw r30,ADREN(r31) /* enable CS1 */ /* clear entire on chip SRAM (unique for ROM startup) */ lis r30, (MBAR+ONCHIP_SRAM_OFFSET)@h /* get start address of onchip SRAM */ ori r30,r30,(MBAR+ONCHIP_SRAM_OFFSET)@l LWI r29, ONCHIP_SRAM_SIZE /* get size of onchip SRAM */ bl clr_mem /* Clear onchip SRAM */ #endif /* defined(BRS5L) */ /* clear .bss section (unique for ROM startup) */ LWI r30, _bss_start /* get start address of bss section */ LWI r29, _bss_size /* get size of bss section */ bl clr_mem /* Clear the bss section */ /* set stack pointer (common for RAM/ROM startup) */ LA r1, _text_start addi r1, r1, -0x10 /* Set up stack pointer = beginning of text section - 0x10 */ /* enable dynamic power management(common for RAM/ROM startup) */ bl PPC_HID0_rd /* Get the content of HID0 */ SETBITS r30, r29, HID0_DPM bl PPC_HID0_wr /* Set DPM in HID0 */ /* clear arguments and do further init. in C (common for RAM/ROM startup) */ /* Clear argc, argv and envp */ xor r3, r3, r3 xor r4, r4, r4 xor r5, r5, r5 bl SYM (boot_card) /* Call the first C routine */ #if defined(BRS5L) twiddle: b twiddle /* We don't expect to return from boot_card but if we do */ /* wait here for watchdog to kick us into hard reset */ SDRAM_init: #if defined (BRS5L) /* set GPIO_WKUP7 pin low for 66MHz buffering */ /* or high for 133MHz registered buffering */ LWI r30, 0x80000000 lwz r29, GPIOWE(r31) or r29,r29,r30 /* set bit 0 in r29/GPIOWE */ stw r29,GPIOWE(r31) lwz r29, GPIOWOD(r31) andc r29,r29,r30 /* clear bit 0 in r29/GPIOWOD */ stw r29,GPIOWOD(r31) lwz r29, GPIOWDO(r31) andc r29,r29,r30 /* clear bit 0 in r29/GPIOWDO */ stw r29,GPIOWDO(r31) lwz r29, GPIOWDD(r31) or r29,r29,r30 /* set bit 0 in r29/GPIOWDD */ stw r29,GPIOWDD(r31) /* activate MEM_CS1 output */ lwz r29, GPIOPCR(r31) or r29,r29,r30 /* set bit 0 in r29/GPIOPCR */ stw r29,GPIOPCR(r31) #endif #if 0 LWI r30, 0xC2222600 /* Single Read2Read/Write delay=0xC, Single Write2Read/Prec. delay=0x2 */ stw r30, CFG1(r31) /* Read CAS latency=0x2, Active2Read delay=0x2, Prec.2active delay=0x2 */ /* Refr.2No-Read delay=0x06, Write latency=0x0 */ #else /* See Erratum 342/339 in MPC5200_Errata_L25R_3_June.pdf: */ /* set 5 delays to their maximum to support two banks */ LWI r30, 0xCC222600 /* Single Read2Read/Write delay=0xC, Single Write2Read/Prec. delay=0x2 */ stw r30, CFG1(r31) /* Read CAS latency=0x2, Active2Read delay=0x2, Prec.2active delay=0x2 */ /* Refr.2No-Read delay=0x06, Write latency=0x0 */ #endif LWI r30, 0xCCC70004 /* Burst2Read Prec.delay=0x8, Burst Write delay=0x8 */ stw r30, CFG2(r31) /* Burst Read2Write delay=0xB, Burst length=0x7, Read Tap=0x4 */ #ifdef BRS5L LWI r30, 0xD1470000 /* Mode Set enabled, Clock enabled, Auto refresh enabled, Mem. data drv */ stw r30, CTRL(r31) /* Refresh counter=0xFFFF */ #else LWI r30, 0xD04F0000 /* Mode Set enabled, Clock enabled, Auto refresh enabled, Mem. data drv */ stw r30, CTRL(r31) /* Refresh counter=0xFFFF */ #endif lwz r30, CTRL(r31) SETBITS r30, r29, CTRL_PRECHARGE /* send two times precharge */ stw r30, CTRL(r31) stw r30, CTRL(r31) lwz r30, CTRL(r31) SETBITS r30, r29, CTRL_REFRESH /* send two times refresh */ stw r30, CTRL(r31) stw r30, CTRL(r31) LWI r30, 0x008D0000 /* Op.Mode=0x0, Read CAS latency=0x2, Burst length=0x3, Write strobe puls */ stw r30, MOD(r31) lwz r30, CTRL(r31) /* Clock enabled, Auto refresh enabled, Mem. data drv. Refresh counter=0xFFFF */ CLRBITS r30, r29, CTRL_BA1 stw r30, CTRL(r31) blr copy_image: mr r27, r28 srwi r28, r28, 2 mtctr r28 slwi r28, r28, 2 sub r27, r27, r28 /* maybe some residual bytes */ copy_image_word: lswi r28, r30, 0x04 stswi r28, r29, 0x04 /* do word copy ROM -> RAM */ addi r30, r30, 0x04 /* increment source pointer */ addi r29, r29, 0x04 /* increment destination pointer */ bdnz copy_image_word /* decrement ctr and branch if not 0 */ cmpwi r27, 0x00 /* copy image finished ? */ beq copy_image_end; mtctr r27 /* reload counter for residual bytes */ copy_image_byte: lswi r28, r30, 0x01 stswi r28, r29, 0x01 /* do byte copy ROM -> RAM */ addi r30, r30, 0x01 /* increment source pointer */ addi r29, r29, 0x01 /* increment destination pointer */ bdnz copy_image_byte /* decrement ctr and branch if not 0 */ copy_image_end: blr #endif /* defined(BRS5L) */ FID_DCache: mflr r26 bl PPC_HID0_rd TSTBITS r30, r29, HID0_DCE bne FID_DCache_exit /* If data cache is switched of, skip further actions */ li r29, PPC_D_CACHE /* 16 Kb data cache on 603e */ LWI r28, _text_start /* Load base address (begin of RAM) */ FID_DCache_loop_1: lwz r27, 0(r28) /* Load data at address */ addi r28, r28, PPC_CACHE_ALIGNMENT /* increment cache line address */ subi r29, r29, PPC_CACHE_ALIGNMENT /* increment loop counter */ cmpwi r29, 0x0 bne FID_DCache_loop_1 /* Loop until cache size is reached */ li r29, PPC_D_CACHE /* 16 Kb data cache on 603e */ LWI r28, _text_start /* Reload base address (begin of RAM) */ xor r27, r27, r27 FID_DCache_loop_2: dcbf r27, r28 /* Flush and invalidate cache */ addi r28, r28, PPC_CACHE_ALIGNMENT /* increment cache line address */ subi r29, r29, PPC_CACHE_ALIGNMENT /* increment loop counter */ cmpwi r29, 0x0 bne FID_DCache_loop_2 /* Loop around until cache size is reached */ bl PPC_HID0_rd /* Read HID0 */ CLRBITS r30, r29, HID0_DCE bl PPC_HID0_wr /* Clear DCE */ FID_DCache_exit: mtlr r26 blr IDUL_ICache: mflr r26 bl PPC_HID0_rd TSTBITS r30, r29, HID0_ICE bne IDUL_ICache_exit /* If instruction cache is switched of, skip further actions */ CLRBITS r30, r29, HID0_ICE bl PPC_HID0_wr /* Disable ICE bit */ SETBITS r30, r29, HID0_ICFI bl PPC_HID0_wr /* Invalidate instruction cache */ CLRBITS r30, r29, HID0_ICFI bl PPC_HID0_wr /* Disable cache invalidate */ CLRBITS r30, r29, HID0_ILOCK bl PPC_HID0_wr /* Disable instruction cache lock */ IDUL_ICache_exit: mtlr r26 blr TLB_init: /* Initialize translation lookaside buffers (TLBs) */ xor r30, r30, r30 xor r29, r29, r29 TLB_init_loop: tlbie r29 tlbsync addi r29, r29, 0x1000 addi r30, r30, 0x01 cmpli 0, 0, r30, 0x0080 bne TLB_init_loop blr FPU_init: mfmsr r30 /* get content of MSR */ SETBITS r30, r29, MSR_FP mtmsr r30 /* enable FPU and FPU exceptions */ #if 0 LA r29, RAM_START stw r29, 0x0(r29) #endif lfd f0, 0(r29) fmr f1, f0 fmr f2, f0 fmr f3, f0 fmr f4, f0 fmr f5, f0 fmr f6, f0 fmr f7, f0 fmr f8, f0 fmr f9, f0 fmr f10, f0 fmr f11, f0 fmr f12, f0 fmr f13, f0 fmr f14, f0 fmr f15, f0 fmr f16, f0 fmr f17, f0 fmr f18, f0 fmr f19, f0 fmr f20, f0 fmr f21, f0 fmr f22, f0 fmr f23, f0 fmr f24, f0 fmr f25, f0 fmr f26, f0 fmr f27, f0 fmr f28, f0 fmr f29, f0 fmr f30, f0 fmr f31, f0 mtfsfi 0, 0 /* initialize bit positons in FPSCR */ mtfsfi 1, 0 mtfsfi 2, 0 mtfsfi 3, 0 mtfsfi 4, 0 mtfsfi 5, 0 mtfsfi 6, 0 mtfsfi 7, 0 blr SPRG_init: /* initialize registers */ xor r30, r30, r30 mtspr XER, r30 mtspr CTR, r30 mtspr DSISR, r30 mtspr DAR, r30 mtspr DEC, r30 mtspr SDR1, r30 mtspr SRR0, r30 mtspr SRR1, r30 mtspr CSSR0, r30 mtspr CSSR1, r30 mtspr SPRG0, r30 mtspr SPRG1, r30 mtspr SPRG2, r30 mtspr SPRG3, r30 mtspr SPRG4, r30 mtspr SPRG5, r30 mtspr SPRG6, r30 mtspr SPRG7, r30 mtspr EAR, r30 mtspr TBWU, r30 mtspr TBWL, r30 mtspr IBAT0U, r30 mtspr IBAT0L, r30 mtspr IBAT1U, r30 mtspr IBAT1L, r30 mtspr IBAT2U, r30 mtspr IBAT2L, r30 mtspr IBAT3U, r30 mtspr IBAT3L, r30 mtspr IBAT4U, r30 mtspr IBAT4L, r30 mtspr IBAT5U, r30 mtspr IBAT5L, r30 mtspr IBAT6U, r30 mtspr IBAT6L, r30 mtspr IBAT7U, r30 mtspr IBAT7L, r30 mtspr DBAT0U, r30 mtspr DBAT0L, r30 mtspr DBAT1U, r30 mtspr DBAT1L, r30 mtspr DBAT2U, r30 mtspr DBAT2L, r30 mtspr DBAT3U, r30 mtspr DBAT3L, r30 mtspr DBAT4U, r30 mtspr DBAT4L, r30 mtspr DBAT5U, r30 mtspr DBAT5L, r30 mtspr DBAT6U, r30 mtspr DBAT6L, r30 mtspr DBAT7U, r30 mtspr DBAT7L, r30 mtspr DMISS, r30 mtspr DCMP, r30 mtspr HASH1, r30 mtspr HASH2, r30 mtspr IMISS, r30 mtspr ICMP, r30 mtspr RPA, r30 mtsr SR0, r30 mtsr SR1, r30 mtsr SR2, r30 mtsr SR3, r30 mtsr SR4, r30 mtsr SR5, r30 mtsr SR6, r30 mtsr SR7, r30 mtsr SR8, r30 mtsr SR9, r30 mtsr SR10, r30 mtsr SR12, r30 mtsr SR13, r30 mtsr SR14, r30 mtsr SR15, r30 blr SPRG_brk_init: xor r30, r30, r30 mtspr DABR2, r30 mtspr DBCR, r30 mtspr IBCR, r30 mtspr IABR, r30 mtspr HID2, r30 mtspr DABR, r30 mtspr IABR2, r30 blr PPC_HID0_rd: /* get HID0 content to r30 */ mfspr r30, HID0 blr PPC_HID0_wr: /* put r30 content to HID0 */ mtspr HID0, r30 blr clr_mem: mr r28, r29 srwi r29, r29, 2 mtctr r29 /* set ctr reg */ slwi r29, r29, 2 sub r28, r28, r29 /* maybe some residual bytes */ xor r29, r29, r29 clr_mem_word: stswi r29, r30, 0x04 /* store r29 (word) to r30 memory location */ addi r30, r30, 0x04 /* increment r30 */ bdnz clr_mem_word /* dec counter and loop */ cmpwi r28, 0x00 /* clear mem. finished ? */ beq clr_mem_end; mtctr r28 /* reload counter for residual bytes */ clr_mem_byte: stswi r29, r30, 0x01 /* store r29 (byte) to r30 memory location */ addi r30, r30, 0x01 /* update r30 */ bdnz clr_mem_byte /* dec counter and loop */ clr_mem_end: blr /* return */