[rc4,01/29] target/avr: Add basic parameters for new AVR platform

Commit Message

Aleksandar Markovic Jan. 31, 2020, 12:02 a.m. UTC

From: Michael Rolnik <[e-mail]>

This includes definitions of various basic parameters needed
for integration of a new platform into QEMU.

[AM: Split a larger AVR introduction patch into logical units]
Suggested-by: Aleksandar Markovic <[e-mail]>

Co-developed-by: Michael Rolnik <[e-mail]>
Co-developed-by: Sarah Harris <[e-mail]>
Signed-off-by: Michael Rolnik <[e-mail]>
Signed-off-by: Sarah Harris <[e-mail]>
Signed-off-by: Michael Rolnik <[e-mail]>
Acked-by: Igor Mammedov <[e-mail]>
Tested-by: Philippe Mathieu-Daudé <[e-mail]>
Signed-off-by: Richard Henderson <[e-mail]>
Signed-off-by: Aleksandar Markovic <[e-mail]>
---
 target/avr/cpu-param.h | 37 ++++++++++++++++++++++++++
 target/avr/cpu.h       | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 109 insertions(+)
 create mode 100644 target/avr/cpu-param.h
 create mode 100644 target/avr/cpu.h

Comments

Aleksandar Markovic Jan. 31, 2020, 6:47 p.m. UTC | #1

On Friday, January 31, 2020, Aleksandar Markovic <
[e-mail]> wrote:

> From: Michael Rolnik <[e-mail]>
>
> This includes definitions of various basic parameters needed
> for integration of a new platform into QEMU.
>
> [AM: Split a larger AVR introduction patch into logical units]
> Suggested-by: Aleksandar Markovic <[e-mail]>
>
> Co-developed-by: Michael Rolnik <[e-mail]>
> Co-developed-by: Sarah Harris <[e-mail]>
> Signed-off-by: Michael Rolnik <[e-mail]>
> Signed-off-by: Sarah Harris <[e-mail]>
> Signed-off-by: Michael Rolnik <[e-mail]>
> Acked-by: Igor Mammedov <[e-mail]>
> Tested-by: Philippe Mathieu-Daudé <[e-mail]>
> Signed-off-by: Richard Henderson <[e-mail]>
> Signed-off-by: Aleksandar Markovic <[e-mail]>
> ---
>  target/avr/cpu-param.h | 37 ++++++++++++++++++++++++++
>  target/avr/cpu.h       | 72 ++++++++++++++++++++++++++++++
> ++++++++++++++++++++
>  2 files changed, 109 insertions(+)
>  create mode 100644 target/avr/cpu-param.h
>  create mode 100644 target/avr/cpu.h
>
> diff --git a/target/avr/cpu-param.h b/target/avr/cpu-param.h
> new file mode 100644
> index 0000000..0c29ce4
> --- /dev/null
> +++ b/target/avr/cpu-param.h
> @@ -0,0 +1,37 @@
> +/*
> + * QEMU AVR CPU
> + *
> + * Copyright (c) 2019 Michael Rolnik
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see
> + * <http://www.gnu.org/licenses/lgpl-2.1.html>
> + */
> +
> +#ifndef AVR_CPU_PARAM_H
> +#define AVR_CPU_PARAM_H
> +
> +#define TARGET_LONG_BITS 32
> +/*
> + * TARGET_PAGE_BITS cannot be more than 8 bits because
> + * 1.  all IO registers occupy [0x0000 .. 0x00ff] address range, and they
> + *     should be implemented as a device and not memory
> + * 2.  SRAM starts at the address 0x0100
> + */
> +#define TARGET_PAGE_BITS 8
> +#define TARGET_PHYS_ADDR_SPACE_BITS 24
> +#define TARGET_VIRT_ADDR_SPACE_BITS 24
> +#define NB_MMU_MODES 2
> +
> +
> +#endif
> diff --git a/target/avr/cpu.h b/target/avr/cpu.h
> new file mode 100644
> index 0000000..d122611
> --- /dev/null
> +++ b/target/avr/cpu.h
> @@ -0,0 +1,72 @@
> +/*
> + * QEMU AVR CPU
> + *
> + * Copyright (c) 2019 Michael Rolnik
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see
> + * <http://www.gnu.org/licenses/lgpl-2.1.html>
> + */
> +
> +#ifndef QEMU_AVR_CPU_H
> +#define QEMU_AVR_CPU_H
> +
> +#include "cpu-qom.h"


This line should be a part of the next patch.


> +#include "exec/cpu-defs.h"
> +
> +#define TCG_GUEST_DEFAULT_MO 0
> +#define AVR_CPU_TYPE_SUFFIX "-" TYPE_AVR_CPU
> +#define AVR_CPU_TYPE_NAME(name) (name AVR_CPU_TYPE_SUFFIX)
> +#define CPU_RESOLVING_TYPE TYPE_AVR_CPU


Last three lines should be a part of the next patch.

+
> +/*
> + * AVR has two memory spaces, data & code.
> + * e.g. both have 0 address
> + * ST/LD instructions access data space
> + * LPM/SPM and instruction fetching access code memory space
> + */
> +#define MMU_CODE_IDX 0
> +#define MMU_DATA_IDX 1
> +
> +#define EXCP_RESET 1
> +#define EXCP_INT(n) (EXCP_RESET + (n) + 1)
> +
> +/* Number of CPU registers */
> +#define NUMBER_OF_CPU_REGISTERS 32
> +/* Number of IO registers accessible by ld/st/in/out */
> +#define NUMBER_OF_IO_REGISTERS 64
> +
> +/*
> + * Offsets of AVR memory regions in host memory space.
> + *
> + * This is needed because the AVR has separate code and data address
> + * spaces that both have start from zero but have to go somewhere in
> + * host memory.
> + *
> + * It's also useful to know where some things are, like the IO registers.
> + */
> +/* Flash program memory */
> +#define OFFSET_CODE 0x00000000
> +/* CPU registers, IO registers, and SRAM */
> +#define OFFSET_DATA 0x00800000
> +/* CPU registers specifically, these are mapped at the start of data */
> +#define OFFSET_CPU_REGISTERS OFFSET_DATA
> +/*
> + * IO registers, including status register, stack pointer, and memory
> + * mapped peripherals, mapped just after CPU registers
> + */
> +#define OFFSET_IO_REGISTERS (OFFSET_DATA + NUMBER_OF_CPU_REGISTERS)
> +
> +#define EF_AVR_MACH 0x7F
> +
> +#endif /* !defined (QEMU_AVR_CPU_H) */
> --
> 2.7.4
>
>

Aleksandar Markovic Jan. 31, 2020, 7:23 p.m. UTC | #2

On Friday, January 31, 2020, Aleksandar Markovic <
[e-mail]> wrote:

> From: Michael Rolnik <[e-mail]>
>
> This includes definitions of various basic parameters needed
> for integration of a new platform into QEMU.
>
> [AM: Split a larger AVR introduction patch into logical units]
> Suggested-by: Aleksandar Markovic <[e-mail]>
>
> Co-developed-by: Michael Rolnik <[e-mail]>
> Co-developed-by: Sarah Harris <[e-mail]>
> Signed-off-by: Michael Rolnik <[e-mail]>
> Signed-off-by: Sarah Harris <[e-mail]>
> Signed-off-by: Michael Rolnik <[e-mail]>
> Acked-by: Igor Mammedov <[e-mail]>
> Tested-by: Philippe Mathieu-Daudé <[e-mail]>
> Signed-off-by: Richard Henderson <[e-mail]>
> Signed-off-by: Aleksandar Markovic <[e-mail]>
> ---
>  target/avr/cpu-param.h | 37 ++++++++++++++++++++++++++
>  target/avr/cpu.h       | 72 ++++++++++++++++++++++++++++++
> ++++++++++++++++++++
>  2 files changed, 109 insertions(+)
>  create mode 100644 target/avr/cpu-param.h
>  create mode 100644 target/avr/cpu.h
>
> diff --git a/target/avr/cpu-param.h b/target/avr/cpu-param.h
> new file mode 100644
> index 0000000..0c29ce4
> --- /dev/null
> +++ b/target/avr/cpu-param.h
> @@ -0,0 +1,37 @@
> +/*
> + * QEMU AVR CPU
> + *
> + * Copyright (c) 2019 Michael Rolnik
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see
> + * <http://www.gnu.org/licenses/lgpl-2.1.html>
> + */
> +
> +#ifndef AVR_CPU_PARAM_H
> +#define AVR_CPU_PARAM_H
> +
> +#define TARGET_LONG_BITS 32
> +/*
> + * TARGET_PAGE_BITS cannot be more than 8 bits because
> + * 1.  all IO registers occupy [0x0000 .. 0x00ff] address range, and they
> + *     should be implemented as a device and not memory
> + * 2.  SRAM starts at the address 0x0100
> + */
> +#define TARGET_PAGE_BITS 8
> +#define TARGET_PHYS_ADDR_SPACE_BITS 24
> +#define TARGET_VIRT_ADDR_SPACE_BITS 24
> +#define NB_MMU_MODES 2
> +
> +
> +#endif
> diff --git a/target/avr/cpu.h b/target/avr/cpu.h
> new file mode 100644
> index 0000000..d122611
> --- /dev/null
> +++ b/target/avr/cpu.h
> @@ -0,0 +1,72 @@
> +/*
> + * QEMU AVR CPU
> + *
> + * Copyright (c) 2019 Michael Rolnik
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see
> + * <http://www.gnu.org/licenses/lgpl-2.1.html>
> + */
> +
> +#ifndef QEMU_AVR_CPU_H
> +#define QEMU_AVR_CPU_H
> +
> +#include "cpu-qom.h"
> +#include "exec/cpu-defs.h"
> +
> +#define TCG_GUEST_DEFAULT_MO 0
> +#define AVR_CPU_TYPE_SUFFIX "-" TYPE_AVR_CPU
> +#define AVR_CPU_TYPE_NAME(name) (name AVR_CPU_TYPE_SUFFIX)
> +#define CPU_RESOLVING_TYPE TYPE_AVR_CPU
> +
> +/*
> + * AVR has two memory spaces, data & code.
> + * e.g. both have 0 address
> + * ST/LD instructions access data space
> + * LPM/SPM and instruction fetching access code memory space
> + */
> +#define MMU_CODE_IDX 0
> +#define MMU_DATA_IDX 1
> +
> +#define EXCP_RESET 1
> +#define EXCP_INT(n) (EXCP_RESET + (n) + 1)
> +
> +/* Number of CPU registers */
> +#define NUMBER_OF_CPU_REGISTERS 32
> +/* Number of IO registers accessible by ld/st/in/out */
> +#define NUMBER_OF_IO_REGISTERS 64
> +
> +/*
> + * Offsets of AVR memory regions in host memory space.
> + *
> + * This is needed because the AVR has separate code and data address
> + * spaces that both have start from zero but have to go somewhere in
> + * host memory.
> + *
> + * It's also useful to know where some things are, like the IO registers.
> + */
> +/* Flash program memory */
> +#define OFFSET_CODE 0x00000000
> +/* CPU registers, IO registers, and SRAM */
> +#define OFFSET_DATA 0x00800000
> +/* CPU registers specifically, these are mapped at the start of data */
> +#define OFFSET_CPU_REGISTERS OFFSET_DATA
> +/*
> + * IO registers, including status register, stack pointer, and memory
> + * mapped peripherals, mapped just after CPU registers
> + */
> +#define OFFSET_IO_REGISTERS (OFFSET_DATA + NUMBER_OF_CPU_REGISTERS)
> +
> +#define EF_AVR_MACH 0x7F


This line seems to belong more to patch 6, where it basically extracts bits
6..0 from e_flags.

+
> +#endif /* !defined (QEMU_AVR_CPU_H) */
> --
> 2.7.4
>
>

Aleksandar Markovic Jan. 31, 2020, 8:07 p.m. UTC | #3

On Friday, January 31, 2020, Aleksandar Markovic <
[e-mail]> wrote:

> From: Michael Rolnik <[e-mail]>
>
> This includes definitions of various basic parameters needed
> for integration of a new platform into QEMU.
>
>
Hi, all.

Just to keep everyone in the loop:

I'll try to put together rc5 in next few days, with a number of relatvely
minor changes (Alex/Philippe improvments and some more). Let me know if
this doesn't work for you for any reason.

Igor, a special question to you:

You already gave Acked-by for former patch 1, which is now transformed to
patches 1-6. I gather you are familiar with all topics involved. Could you
perhaps taje a closer look at patches 1-6 now, and, if you are happy with
what you see, perhaps you can give Reviewed-by to them?

Thanks, Aleksandar



> [AM: Split a larger AVR introduction patch into logical units]
> Suggested-by: Aleksandar Markovic <[e-mail]>
>
> Co-developed-by: Michael Rolnik <[e-mail]>
> Co-developed-by: Sarah Harris <[e-mail]>
> Signed-off-by: Michael Rolnik <[e-mail]>
> Signed-off-by: Sarah Harris <[e-mail]>
> Signed-off-by: Michael Rolnik <[e-mail]>
> Acked-by: Igor Mammedov <[e-mail]>
> Tested-by: Philippe Mathieu-Daudé <[e-mail]>
> Signed-off-by: Richard Henderson <[e-mail]>
> Signed-off-by: Aleksandar Markovic <[e-mail]>
> ---
>  target/avr/cpu-param.h | 37 ++++++++++++++++++++++++++
>  target/avr/cpu.h       | 72 ++++++++++++++++++++++++++++++
> ++++++++++++++++++++
>  2 files changed, 109 insertions(+)
>  create mode 100644 target/avr/cpu-param.h
>  create mode 100644 target/avr/cpu.h
>
> diff --git a/target/avr/cpu-param.h b/target/avr/cpu-param.h
> new file mode 100644
> index 0000000..0c29ce4
> --- /dev/null
> +++ b/target/avr/cpu-param.h
> @@ -0,0 +1,37 @@
> +/*
> + * QEMU AVR CPU
> + *
> + * Copyright (c) 2019 Michael Rolnik
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see
> + * <http://www.gnu.org/licenses/lgpl-2.1.html>
> + */
> +
> +#ifndef AVR_CPU_PARAM_H
> +#define AVR_CPU_PARAM_H
> +
> +#define TARGET_LONG_BITS 32
> +/*
> + * TARGET_PAGE_BITS cannot be more than 8 bits because
> + * 1.  all IO registers occupy [0x0000 .. 0x00ff] address range, and they
> + *     should be implemented as a device and not memory
> + * 2.  SRAM starts at the address 0x0100
> + */
> +#define TARGET_PAGE_BITS 8
> +#define TARGET_PHYS_ADDR_SPACE_BITS 24
> +#define TARGET_VIRT_ADDR_SPACE_BITS 24
> +#define NB_MMU_MODES 2
> +
> +
> +#endif
> diff --git a/target/avr/cpu.h b/target/avr/cpu.h
> new file mode 100644
> index 0000000..d122611
> --- /dev/null
> +++ b/target/avr/cpu.h
> @@ -0,0 +1,72 @@
> +/*
> + * QEMU AVR CPU
> + *
> + * Copyright (c) 2019 Michael Rolnik
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see
> + * <http://www.gnu.org/licenses/lgpl-2.1.html>
> + */
> +
> +#ifndef QEMU_AVR_CPU_H
> +#define QEMU_AVR_CPU_H
> +
> +#include "cpu-qom.h"
> +#include "exec/cpu-defs.h"
> +
> +#define TCG_GUEST_DEFAULT_MO 0
> +#define AVR_CPU_TYPE_SUFFIX "-" TYPE_AVR_CPU
> +#define AVR_CPU_TYPE_NAME(name) (name AVR_CPU_TYPE_SUFFIX)
> +#define CPU_RESOLVING_TYPE TYPE_AVR_CPU
> +
> +/*
> + * AVR has two memory spaces, data & code.
> + * e.g. both have 0 address
> + * ST/LD instructions access data space
> + * LPM/SPM and instruction fetching access code memory space
> + */
> +#define MMU_CODE_IDX 0
> +#define MMU_DATA_IDX 1
> +
> +#define EXCP_RESET 1
> +#define EXCP_INT(n) (EXCP_RESET + (n) + 1)
> +
> +/* Number of CPU registers */
> +#define NUMBER_OF_CPU_REGISTERS 32
> +/* Number of IO registers accessible by ld/st/in/out */
> +#define NUMBER_OF_IO_REGISTERS 64
> +
> +/*
> + * Offsets of AVR memory regions in host memory space.
> + *
> + * This is needed because the AVR has separate code and data address
> + * spaces that both have start from zero but have to go somewhere in
> + * host memory.
> + *
> + * It's also useful to know where some things are, like the IO registers.
> + */
> +/* Flash program memory */
> +#define OFFSET_CODE 0x00000000
> +/* CPU registers, IO registers, and SRAM */
> +#define OFFSET_DATA 0x00800000
> +/* CPU registers specifically, these are mapped at the start of data */
> +#define OFFSET_CPU_REGISTERS OFFSET_DATA
> +/*
> + * IO registers, including status register, stack pointer, and memory
> + * mapped peripherals, mapped just after CPU registers
> + */
> +#define OFFSET_IO_REGISTERS (OFFSET_DATA + NUMBER_OF_CPU_REGISTERS)
> +
> +#define EF_AVR_MACH 0x7F
> +
> +#endif /* !defined (QEMU_AVR_CPU_H) */
> --
> 2.7.4
>
>

Patch

diff --git a/target/avr/cpu-param.h b/target/avr/cpu-param.h
new file mode 100644
index 0000000..0c29ce4
--- /dev/null
+++ b/target/avr/cpu-param.h
@@ -0,0 +1,37 @@ 
+/*
+ * QEMU AVR CPU
+ *
+ * Copyright (c) 2019 Michael Rolnik
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see
+ * <http://www.gnu.org/licenses/lgpl-2.1.html>
+ */
+
+#ifndef AVR_CPU_PARAM_H
+#define AVR_CPU_PARAM_H
+
+#define TARGET_LONG_BITS 32
+/*
+ * TARGET_PAGE_BITS cannot be more than 8 bits because
+ * 1.  all IO registers occupy [0x0000 .. 0x00ff] address range, and they
+ *     should be implemented as a device and not memory
+ * 2.  SRAM starts at the address 0x0100
+ */
+#define TARGET_PAGE_BITS 8
+#define TARGET_PHYS_ADDR_SPACE_BITS 24
+#define TARGET_VIRT_ADDR_SPACE_BITS 24
+#define NB_MMU_MODES 2
+
+
+#endif
diff --git a/target/avr/cpu.h b/target/avr/cpu.h
new file mode 100644
index 0000000..d122611
--- /dev/null
+++ b/target/avr/cpu.h
@@ -0,0 +1,72 @@ 
+/*
+ * QEMU AVR CPU
+ *
+ * Copyright (c) 2019 Michael Rolnik
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see
+ * <http://www.gnu.org/licenses/lgpl-2.1.html>
+ */
+
+#ifndef QEMU_AVR_CPU_H
+#define QEMU_AVR_CPU_H
+
+#include "cpu-qom.h"
+#include "exec/cpu-defs.h"
+
+#define TCG_GUEST_DEFAULT_MO 0
+#define AVR_CPU_TYPE_SUFFIX "-" TYPE_AVR_CPU
+#define AVR_CPU_TYPE_NAME(name) (name AVR_CPU_TYPE_SUFFIX)
+#define CPU_RESOLVING_TYPE TYPE_AVR_CPU
+
+/*
+ * AVR has two memory spaces, data & code.
+ * e.g. both have 0 address
+ * ST/LD instructions access data space
+ * LPM/SPM and instruction fetching access code memory space
+ */
+#define MMU_CODE_IDX 0
+#define MMU_DATA_IDX 1
+
+#define EXCP_RESET 1
+#define EXCP_INT(n) (EXCP_RESET + (n) + 1)
+
+/* Number of CPU registers */
+#define NUMBER_OF_CPU_REGISTERS 32
+/* Number of IO registers accessible by ld/st/in/out */
+#define NUMBER_OF_IO_REGISTERS 64
+
+/*
+ * Offsets of AVR memory regions in host memory space.
+ *
+ * This is needed because the AVR has separate code and data address
+ * spaces that both have start from zero but have to go somewhere in
+ * host memory.
+ *
+ * It's also useful to know where some things are, like the IO registers.
+ */
+/* Flash program memory */
+#define OFFSET_CODE 0x00000000
+/* CPU registers, IO registers, and SRAM */
+#define OFFSET_DATA 0x00800000
+/* CPU registers specifically, these are mapped at the start of data */
+#define OFFSET_CPU_REGISTERS OFFSET_DATA
+/*
+ * IO registers, including status register, stack pointer, and memory
+ * mapped peripherals, mapped just after CPU registers
+ */
+#define OFFSET_IO_REGISTERS (OFFSET_DATA + NUMBER_OF_CPU_REGISTERS)
+
+#define EF_AVR_MACH 0x7F
+
+#endif /* !defined (QEMU_AVR_CPU_H) */