📄 vectors.s
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str r3, [r0, _CONST_ HwPortE] // // Set up the stack pointer. // ldr r13, =SVCStackEnd // // Initialize the value of ulEndOfRAM. // ldr r0, =ulEndOfRAM ldr r1, =_RWLIMIT_ str r1, [r0] // // Call the update code. // mov r0, _CONST_ 0x00000000 mov lr, pc _IMPORT_ Update ldr pc, =Update // // Disable the MMU. // ldr r0, =0x00000070 mcr _CP15_, 0, r0, _CR1_, _CR0_ // // There should always be two NOP instructions following the enable or // disable of the MMU. // nop nop // // Flush the cache and TLB. // ldr r0, =0x00000000 mcr _CP15_, 0, r0, _CR7_, _CR7_ mcr _CP15_, 0, r0, _CR8_, _CR7_ // // Branch back to the reset vector. // mov pc, r0 // // Tell the assembler to put in-line data here. // _LTORG_//****************************************************************************//// UpdateHandler is the routine which is called by the player when a software// update needs to be performed.////****************************************************************************UpdateHandler _LABEL_ // // Disable the FIQ and IRQ interrupts. // mrs r0, cpsr orr r0, r0, _CONST_ 0x000000c0 msr cpsr_cf, r0 // // Load pointers to the EP7209 internal registers. // ldr r0, =HwBaseAddress add r1, r0, _CONST_ 0x00001000 add r2, r0, _CONST_ 0x00002000 // // Disable all the interrupt sources. // ldr r3, =0x00000000 str r3, [r0, _CONST_ HwIntMask] str r3, [r1, _CONST_ (HwIntMask2 - 0x1000)] str r3, [r2, _CONST_ (HwIntMask3 - 0x2000)] // // Disable the MMU. // ldr r0, =0x00000070 mcr _CP15_, 0, r0, _CR1_, _CR0_ // // There should always be two NOP instructions following the enable or // disable of the MMU. // nop nop // // Flush the cache and TLB. // ldr r0, =0x00000000 mcr _CP15_, 0, r0, _CR7_, _CR7_ mcr _CP15_, 0, r0, _CR8_, _CR7_ // // Copy the code image from ROM to RAM. // ldr r1, =0x00000000 ldr r2, =0x60000000 ldr r3, =_ROLIMIT_ bic r3, r3, _CONST_ 0x00f00000update_copy_ro _LABEL_ ldr r0, [r1], _CONST_ 4 str r0, [r2], _CONST_ 4 subs r3, r3, _CONST_ 4 bne update_copy_ro // // Copy the read-write data block from ROM to RAM. // mov r0, r1 ldr r1, =_RWBASE_ bic r1, r1, _CONST_ 0x00f00000 orr r1, r1, _CONST_ 0x60000000 ldr r2, =_ZIBASE_ bic r2, r2, _CONST_ 0x00f00000 orr r2, r2, _CONST_ 0x60000000update_copy_rw _LABEL_ cmp r1, r2 ldrne r3, [r0], _CONST_ 4 strne r3, [r1], _CONST_ 4 bne update_copy_rw // // Fill the zero initialized data block in RAM with zeros. // ldr r2, =_RWLIMIT_ bic r2, r2, _CONST_ 0x00f00000 orr r2, r2, _CONST_ 0x60000000 ldr r3, =0x00000000update_fill_zi _LABEL_ cmp r1, r2 strne r3, [r1], _CONST_ 4 bne update_fill_zi // // Tell the MMU where to find the new page table. // _IMPORT_ PageTable ldr r0, =PageTable bic r0, r0, _CONST_ 0x00f00000 orr r0, r0, _CONST_ 0x60000000 mcr _CP15_, 0, r0, _CR2_, _CR0_ // // Enable the MMU. // ldr r0, =0x00000071 mcr _CP15_, 0, r0, _CR1_, _CR0_ // // There should always be two NOP instructions following the enable or // disable of the MMU. // nop nop // // Set up the stack pointer. // ldr r13, =SVCStackEnd // // Initialize the value of ulEndOfRAM. // ldr r0, =ulEndOfRAM add r1, r0, _CONST_ 0x00000004 str r1, [r0] // // Call the update code. We set the link register to zero so that when the // update code returns, we will re-initialize the system. // mov r0, _CONST_ 0x00000001 mov lr, pc ldr pc, =Update // // Disable the MMU. // ldr r0, =0x00000070 mcr _CP15_, 0, r0, _CR1_, _CR0_ // // There should always be two NOP instructions following the enable or // disable of the MMU. // nop nop // // Flush the cache and TLB. // ldr r0, =0x00000000 mcr _CP15_, 0, r0, _CR7_, _CR7_ mcr _CP15_, 0, r0, _CR8_, _CR7_ // // Branch back to the reset vector. // mov pc, r0 // // Tell the assembler to put in-line data here. // _LTORG_//****************************************************************************//// CheckImage determines if the image at the specified location is "valid".// We check to see that the hardware ID in the image matches the hardware ID of// the player and that the CRC32 of the image is correct.////****************************************************************************CheckImage _LABEL_ // // Load the base address from the image. // ldr r1, [r0, _CONST_ 0x20] // // Compare the base address of the image to its actual location in memory. // add r2, r0, _CONST_ 0x20 cmp r1, r2 movne r0, _CONST_ 0x00000000 movne pc, lr // // Load the hardware ID from the image. // ldr r1, [r0, _CONST_ 0x28] // // Compare the hardware ID of the image to be sure that it matches the // hardware ID of the player. // ldr r2, =HardwareID cmp r1, r2 movne r0, _CONST_ 0x00000000 movne pc, lr // // Load a pointer to the CRC32 data table. // ldr r1, =CRCTable bic r1, r1, _CONST_ 0x00f00000 // // Get the length of the image. // ldr r2, [r0, _CONST_ 0x24] // // If the length of the image is zero, greater than 1Meg, or not a multiple // of 4 bytes, then assume there is an error with the image. // cmp r2, _CONST_ 0x00000000 moveq r0, _CONST_ 0x00000000 moveq pc, lr cmp r2, _CONST_ 0x00100000 movhi r0, _CONST_ 0x00000000 movhi pc, lr tst r2, _CONST_ 0x00000003 movne r0, _CONST_ 0x00000000 movne pc, lr // // Get the CRC of the image. // ldr r6, [r0, _CONST_ 0x2c] // // The CRC32 starts with the first word after the image descriptor // structure. // add r0, r0, _CONST_ 0x30 sub r2, r2, _CONST_ 0x30 // // Set the initial value of the CRC32. // mvn r3, _CONST_ 0x00000000 // // While there are more words in the image, load them and add them to the // checksum. //check_word _LABEL_ // // Load the next word from the image. // ldr r4, [r0], _CONST_ 4 // // Generate the next CRC32 value based on the first byte. // eor r5, r3, r4 and r5, r5, _CONST_ 0xff ldr r5, [r1, r5, lsl _CONST_ 2] mov r3, r3, lsr _CONST_ 8 eor r3, r3, r5 // // Generate the next CRC32 value based on the second byte. // eor r5, r3, r4, lsr _CONST_ 8 and r5, r5, _CONST_ 0xff ldr r5, [r1, r5, lsl _CONST_ 2] mov r3, r3, lsr _CONST_ 8 eor r3, r3, r5 // // Generate the next CRC32 value based on the third byte. // eor r5, r3, r4, lsr _CONST_ 16 and r5, r5, _CONST_ 0xff ldr r5, [r1, r5, lsl _CONST_ 2] mov r3, r3, lsr _CONST_ 8 eor r3, r3, r5 // // Generate the next CRC32 value based on the fourth byte. // eor r5, r3, r4, lsr _CONST_ 24 and r5, r5, _CONST_ 0xff ldr r5, [r1, r5, lsl _CONST_ 2] mov r3, r3, lsr _CONST_ 8 eor r3, r3, r5 // // Decrement the count of bytes and loop back if there are more. // subs r2, r2, _CONST_ 4 bne check_word // // See if the CRC32 mataches. // cmp r3, r6 // // Indicate if the CRC32 matched. // movne r0, _CONST_ 0x00000000 moveq r0, _CONST_ 0x00000001 // // Return. // mov pc, lr _END_⌨️ 快捷键说明
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