Archipelago » qemu

/* MMU modes definitions */

/* Alpha has 5 MMU modes: PALcode, kernel, executive, supervisor, and user.

   The Unix PALcode only exposes the kernel and user modes; presumably

   executive and supervisor are used by VMS.

   PALcode itself uses physical mode for code and kernel mode for data;

   there are PALmode instructions that can access data via physical mode

   or via an os-installed "alternate mode", which is one of the 4 above.

   QEMU does not currently properly distinguish between code/data when

   looking up addresses.  To avoid having to address this issue, our

   emulated PALcode will cheat and use the KSEG mapping for its code+data

   rather than physical addresses.

   Moreover, we're only emulating Unix PALcode, and not attempting VMS.

   All of which allows us to drop all but kernel and user modes.

   Elide the unused MMU modes to save space.  */

#define NB_MMU_MODES 2

#define MMU_MODE0_SUFFIX _kernel

#define MMU_MODE1_SUFFIX _user

#define MMU_KERNEL_IDX   0

#define MMU_USER_IDX     1

typedef struct CPUAlphaState CPUAlphaState;

    return (env->ps >> 3) & 1;