+/* Structures used for displaced stepping. */
+
+/* The maximum number of temporaries available for displaced instructions. */
+#define DISPLACED_TEMPS 16
+/* The maximum number of modified instructions generated for one single-stepped
+ instruction, including the breakpoint (usually at the end of the instruction
+ sequence) and any scratch words, etc. */
+#define DISPLACED_MODIFIED_INSNS 8
+
+struct displaced_step_closure
+{
+ ULONGEST tmp[DISPLACED_TEMPS];
+ int rd;
+ int wrote_to_pc;
+ union
+ {
+ struct
+ {
+ int xfersize;
+ int rn; /* Writeback register. */
+ unsigned int immed : 1; /* Offset is immediate. */
+ unsigned int writeback : 1; /* Perform base-register writeback. */
+ unsigned int restore_r4 : 1; /* Used r4 as scratch. */
+ } ldst;
+
+ struct
+ {
+ unsigned long dest;
+ unsigned int link : 1;
+ unsigned int exchange : 1;
+ unsigned int cond : 4;
+ } branch;
+
+ struct
+ {
+ unsigned int regmask;
+ int rn;
+ CORE_ADDR xfer_addr;
+ unsigned int load : 1;
+ unsigned int user : 1;
+ unsigned int increment : 1;
+ unsigned int before : 1;
+ unsigned int writeback : 1;
+ unsigned int cond : 4;
+ } block;
+
+ struct
+ {
+ unsigned int immed : 1;
+ } preload;
+
+ struct
+ {
+ /* If non-NULL, override generic SVC handling (e.g. for a particular
+ OS). */
+ int (*copy_svc_os) (struct gdbarch *gdbarch, struct regcache *regs,
+ struct displaced_step_closure *dsc);
+ } svc;
+ } u;
+
+ /* The size of original instruction, 2 or 4. */
+ unsigned int insn_size;
+ /* True if the original insn (and thus all replacement insns) are Thumb
+ instead of ARM. */
+ unsigned int is_thumb;
+
+ /* The slots in the array is used in this way below,
+ - ARM instruction occupies one slot,
+ - Thumb 16 bit instruction occupies one slot,
+ - Thumb 32-bit instruction occupies *two* slots, one part for each. */
+ unsigned long modinsn[DISPLACED_MODIFIED_INSNS];
+ int numinsns;
+ CORE_ADDR insn_addr;
+ CORE_ADDR scratch_base;
+ void (*cleanup) (struct gdbarch *, struct regcache *,
+ struct displaced_step_closure *);
+};
+
+/* Values for the WRITE_PC argument to displaced_write_reg. If the register
+ write may write to the PC, specifies the way the CPSR T bit, etc. is
+ modified by the instruction. */
+
+enum pc_write_style
+{
+ BRANCH_WRITE_PC,
+ BX_WRITE_PC,
+ LOAD_WRITE_PC,
+ ALU_WRITE_PC,
+ CANNOT_WRITE_PC
+};
+
+extern void
+ arm_process_displaced_insn (struct gdbarch *gdbarch, CORE_ADDR from,
+ CORE_ADDR to, struct regcache *regs,
+ struct displaced_step_closure *dsc);
+extern void
+ arm_displaced_init_closure (struct gdbarch *gdbarch, CORE_ADDR from,
+ CORE_ADDR to, struct displaced_step_closure *dsc);
+extern ULONGEST
+ displaced_read_reg (struct regcache *regs, struct displaced_step_closure *dsc,
+ int regno);
+extern void
+ displaced_write_reg (struct regcache *regs,
+ struct displaced_step_closure *dsc, int regno,
+ ULONGEST val, enum pc_write_style write_pc);