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[PATCH 2/3] arm-tdep.c: Refactor arm_decode_dp_misc
- From: Simon Marchi <simon dot marchi at ericsson dot com>
- To: <gdb-patches at sourceware dot org>
- Cc: Simon Marchi <simon dot marchi at ericsson dot com>
- Date: Wed, 10 Feb 2016 11:17:06 -0500
- Subject: [PATCH 2/3] arm-tdep.c: Refactor arm_decode_dp_misc
- Authentication-results: sourceware.org; auth=none
- References: <1455121027-27061-1-git-send-email-simon dot marchi at ericsson dot com>
Refactor arm_decode_dp_misc to make it more readable. The new layout
matches very closely the description in the ARM Architecture Reference
Manual. It uses the same order and same nomenclature.
gdb/ChangeLog:
* arm-tdep.c (arm_decode_dp_misc): Refactor instruction decoding.
---
gdb/arm-tdep.c | 73 +++++++++++++++++++++++++++++++++++++++-------------------
1 file changed, 49 insertions(+), 24 deletions(-)
diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 0a9c0f6..e17a1a4 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -6517,45 +6517,70 @@ arm_decode_dp_misc (struct gdbarch *gdbarch, uint32_t insn,
struct regcache *regs,
struct displaced_step_closure *dsc)
{
- if (bit (insn, 25))
- switch (bits (insn, 20, 24))
- {
- case 0x10:
- return arm_copy_unmodified (gdbarch, insn, "movw", dsc);
-
- case 0x14:
- return arm_copy_unmodified (gdbarch, insn, "movt", dsc);
+ uint8_t op = bit (insn, 25);
+ uint8_t op1 = bits (insn, 20, 24);
+ uint8_t op2 = bits (insn, 4, 7);
- case 0x12: case 0x16:
- return arm_copy_unmodified (gdbarch, insn, "msr imm", dsc);
-
- default:
- return arm_copy_alu_imm (gdbarch, insn, regs, dsc);
- }
- else
+ if (op == 0)
{
- uint32_t op1 = bits (insn, 20, 24), op2 = bits (insn, 4, 7);
-
if ((op1 & 0x19) != 0x10 && (op2 & 0x1) == 0x0)
+ /* Data-processing (register) */
return arm_copy_alu_reg (gdbarch, insn, regs, dsc);
else if ((op1 & 0x19) != 0x10 && (op2 & 0x9) == 0x1)
+ /* Data-processing (register-shifted register) */
return arm_copy_alu_shifted_reg (gdbarch, insn, regs, dsc);
else if ((op1 & 0x19) == 0x10 && (op2 & 0x8) == 0x0)
+ /* Miscellaneous instructions */
return arm_decode_miscellaneous (gdbarch, insn, regs, dsc);
else if ((op1 & 0x19) == 0x10 && (op2 & 0x9) == 0x8)
+ /* Halfword multiply and multiply accumulate */
return arm_copy_unmodified (gdbarch, insn, "halfword mul/mla", dsc);
else if ((op1 & 0x10) == 0x00 && op2 == 0x9)
+ /* Multiply and multiply accumulate */
return arm_copy_unmodified (gdbarch, insn, "mul/mla", dsc);
else if ((op1 & 0x10) == 0x10 && op2 == 0x9)
+ /* Synchronization primitives */
return arm_copy_unmodified (gdbarch, insn, "synch", dsc);
- else if (op2 == 0xb || (op2 & 0xd) == 0xd)
- /* 2nd arg means "unprivileged". */
- return arm_copy_extra_ld_st (gdbarch, insn, (op1 & 0x12) == 0x02, regs,
- dsc);
+ else if ((op1 & 0x12) != 0x2 && op2 == 0xb)
+ /* Extra load/store instructions */
+ return arm_copy_extra_ld_st (gdbarch, insn, 0, regs, dsc);
+ else if ((op1 & 0x12) != 0x2 && (op2 & 0xd) == 0xd)
+ /* Extra load/store instructions */
+ return arm_copy_extra_ld_st (gdbarch, insn, 0, regs, dsc);
+ else if ((op1 & 0x13) == 0x2 && (op2 & 0xd) == 0xd)
+ /* Extra load/store instructions */
+ return arm_copy_extra_ld_st (gdbarch, insn, 0, regs, dsc);
+ else if ((op1 & 0x12) == 0x2 && op2 == 0xd)
+ /* Extra load/store instructions, unprivileged */
+ return arm_copy_extra_ld_st (gdbarch, insn, 1, regs, dsc);
+ else if ((op1 & 0x13) == 0x3 && (op2 & 0xd) == 0xd)
+ /* Extra load/store instructions, unprivileged */
+ return arm_copy_extra_ld_st (gdbarch, insn, 1, regs, dsc);
+ else
+ return 1;
+ }
+ else
+ {
+ switch (op1)
+ {
+ default:
+ /* Data-processing (immediate) */
+ return arm_copy_alu_imm (gdbarch, insn, regs, dsc);
+
+ case 0x10:
+ /* 16-bit immediate load, MOV (immediate) */
+ return arm_copy_unmodified (gdbarch, insn, "movw", dsc);
+
+ case 0x14:
+ /* High halfword 16-bit immediate load, MOVT */
+ return arm_copy_unmodified (gdbarch, insn, "movt", dsc);
+
+ case 0x12:
+ case 0x16:
+ /* MSR (immediate), and hints */
+ return arm_copy_unmodified (gdbarch, insn, "msr imm", dsc);
+ }
}
-
- /* Should be unreachable. */
- return 1;
}
static int
--
2.5.1