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Still more stupid questions on Cortex-A7 instruction set

Juha Aaltonen

I've beem constructing a list of Cortex-A7 ARM-instructions, and there are some questions I haven't found

an answer to in ARMv7-A/R ARM Issue C.

How is this special?

LDRD<c>_<Rt>,_<Rt2>,_<label>_LDRD<c>_<Rt>,_<Rt2>,_[PC,_#-0]_Special_caseA1A8.8.73

Under which sub-chapter of A4 this fits best?

MOVW<c>_<Rd>,_#<imm12>A2A8.8.102

How about this:

VDIV<c>.F64_<Dd>,_<Dn>,_<Dm>_VDIV<c>.F32_<Sd>,_<Sn>,_<Sm>T1/A1

A8.8.312

About these (what's the Rt's role) I already asked in another thread.

PUSH<c>_<registers>,_<Rt>A2A8.8.133
POP<c>_<registers>,_<Rt>A2A8.8.132

These are the sub-chapters:

branches   

Data-processing instructions   

    Standard data-processing instructions.

    Shift instructions on page A4-167.

    Multiply instructions on page A4-167.

    Saturating instructions on page A4-169.

    Saturating addition and subtraction instructions on page A4-169.

    Packing and unpacking instructions on page A4-170.

    Parallel addition and subtraction instructions on page A4-171.

    Divide instructions on page A4-172.

    Miscellaneous data-processing instructions on page A4-173.

Status register access instructions   

Load/store instructions   

Load/store multiple instructions   

Miscellaneous instructions   

Exception-related instructions   

Coprocessor instructions   

Advanced SIMD and Floating-point load/store instructions   

    Extension register load/store instructions

    Element and structure load/store instructions

Advanced SIMD and Floating-point register transfer instructions    

    Advanced SIMD and Floating-point register transfer instructions

Advanced SIMD data-processing instructions   

    Advanced SIMD parallel addition and subtraction

    Bitwise Advanced SIMD data-processing instructions

    Advanced SIMD comparison instructions

    Advanced SIMD shift instructions

    Advanced SIMD multiply instructions

    Miscellaneous Advanced SIMD data-processing instructions

Floating-point data-processing instructions   

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  • 0 in reply to Yasuhiko Koumoto

    Thanks for explaining.

    The reason I'm asking is that I'm trying to write a gdb stub, and finding out the next instruction for single stepping requires instruction decoding (to a point), so I want to figure out how to organize the decoding in a reasonable way.

    I've already found that there are aliases in the document treated as "native" instructions and some instructions "turn" into other instructions if a register is PC or if immediate value is zero and the like.

    Like shifted register MOV or RRX.

    (Darn, I seem to have forgotten to mark this thread as a question.)

Reply
  • 0 in reply to Yasuhiko Koumoto

    Thanks for explaining.

    The reason I'm asking is that I'm trying to write a gdb stub, and finding out the next instruction for single stepping requires instruction decoding (to a point), so I want to figure out how to organize the decoding in a reasonable way.

    I've already found that there are aliases in the document treated as "native" instructions and some instructions "turn" into other instructions if a register is PC or if immediate value is zero and the like.

    Like shifted register MOV or RRX.

    (Darn, I seem to have forgotten to mark this thread as a question.)

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