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* ARMV7M System emulation.
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* Copyright (c) 2006-2007 CodeSourcery.
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* Written by Paul Brook
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* This code is licenced under the GPL.
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/* Bitbanded IO. Each word corresponds to a single bit. */
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/* Get the byte address of the real memory for a bitband acess. */
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static inline uint32_t bitband_addr(uint32_t addr)
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res = addr & 0xe0000000;
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res |= (addr & 0x1ffffff) >> 5;
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static uint32_t bitband_readb(void *opaque, target_phys_addr_t offset)
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cpu_physical_memory_read(bitband_addr(offset), &v, 1);
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return (v & (1 << ((offset >> 2) & 7))) != 0;
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static void bitband_writeb(void *opaque, target_phys_addr_t offset,
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addr = bitband_addr(offset);
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mask = (1 << ((offset >> 2) & 7));
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cpu_physical_memory_read(addr, &v, 1);
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cpu_physical_memory_write(addr, &v, 1);
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static uint32_t bitband_readw(void *opaque, target_phys_addr_t offset)
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addr = bitband_addr(offset) & ~1;
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mask = (1 << ((offset >> 2) & 15));
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cpu_physical_memory_read(addr, (uint8_t *)&v, 2);
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return (v & mask) != 0;
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static void bitband_writew(void *opaque, target_phys_addr_t offset,
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addr = bitband_addr(offset) & ~1;
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mask = (1 << ((offset >> 2) & 15));
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cpu_physical_memory_read(addr, (uint8_t *)&v, 2);
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cpu_physical_memory_write(addr, (uint8_t *)&v, 2);
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static uint32_t bitband_readl(void *opaque, target_phys_addr_t offset)
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addr = bitband_addr(offset) & ~3;
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mask = (1 << ((offset >> 2) & 31));
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cpu_physical_memory_read(addr, (uint8_t *)&v, 4);
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return (v & mask) != 0;
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static void bitband_writel(void *opaque, target_phys_addr_t offset,
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addr = bitband_addr(offset) & ~3;
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mask = (1 << ((offset >> 2) & 31));
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cpu_physical_memory_read(addr, (uint8_t *)&v, 4);
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cpu_physical_memory_write(addr, (uint8_t *)&v, 4);
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static CPUReadMemoryFunc *bitband_readfn[] = {
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static CPUWriteMemoryFunc *bitband_writefn[] = {
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static void armv7m_bitband_init(void)
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iomemtype = cpu_register_io_memory(0, bitband_readfn, bitband_writefn,
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cpu_register_physical_memory(0x22000000, 0x02000000, iomemtype);
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cpu_register_physical_memory(0x42000000, 0x02000000, iomemtype);
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/* Init CPU and memory for a v7-M based board.
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flash_size and sram_size are in kb.
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Returns the NVIC array. */
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qemu_irq *armv7m_init(int flash_size, int sram_size,
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const char *kernel_filename, const char *cpu_model)
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cpu_model = "cortex-m3";
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env = cpu_init(cpu_model);
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fprintf(stderr, "Unable to find CPU definition\n");
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/* > 32Mb SRAM gets complicated because it overlaps the bitband area.
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We don't have proper commandline options, so allocate half of memory
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as SRAM, up to a maximum of 32Mb, and the rest as code. */
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if (ram_size > (512 + 32) * 1024 * 1024)
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ram_size = (512 + 32) * 1024 * 1024;
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sram_size = (ram_size / 2) & TARGET_PAGE_MASK;
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if (sram_size > 32 * 1024 * 1024)
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sram_size = 32 * 1024 * 1024;
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code_size = ram_size - sram_size;
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/* Flash programming is done via the SCU, so pretend it is ROM. */
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cpu_register_physical_memory(0, flash_size, IO_MEM_ROM);
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cpu_register_physical_memory(0x20000000, sram_size,
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flash_size + IO_MEM_RAM);
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armv7m_bitband_init();
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pic = armv7m_nvic_init(env);
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image_size = load_elf(kernel_filename, 0, &entry, &lowaddr, NULL);
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if (image_size < 0) {
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image_size = load_image(kernel_filename, phys_ram_base);
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if (image_size < 0) {
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fprintf(stderr, "qemu: could not load kernel '%s'\n",
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/* If the image was loaded at address zero then assume it is a
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regular ROM image and perform the normal CPU reset sequence.
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Otherwise jump directly to the entry point. */
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env->regs[13] = tswap32(*(uint32_t *)phys_ram_base);
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pc = tswap32(*(uint32_t *)(phys_ram_base + 4));
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env->regs[15] = pc & ~1;
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/* Hack to map an additional page of ram at the top of the address
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space. This stops qemu complaining about executing code outside RAM
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when returning from an exception. */
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cpu_register_physical_memory(0xfffff000, 0x1000, IO_MEM_RAM + ram_size);