29 lines
944 B
ReStructuredText
29 lines
944 B
ReStructuredText
Register move instructions
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==========================
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Document conventions
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--------------------
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Notation: ``Rd, Rn`` denote ARM registers R0-R15. ``immN`` denotes an immediate
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value having a width of N bits. These instructions affect the condition flags.
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Register moves
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--------------
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Where immediate values are used, these are zero-extended to 32 bits. Thus
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``mov(R0, 0xff)`` will set R0 to 255.
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* mov(Rd, imm8) ``Rd = imm8``
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* mov(Rd, Rn) ``Rd = Rn``
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* movw(Rd, imm16) ``Rd = imm16``
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* movt(Rd, imm16) ``Rd = (Rd & 0xffff) | (imm16 << 16)``
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movt writes an immediate value to the top halfword of the destination register.
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It does not affect the contents of the bottom halfword.
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* movwt(Rd, imm30) ``Rd = imm30``
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movwt is a pseudo-instruction: the MicroPython assembler emits a ``movw`` and a ``movt``
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to move a zero extended 30 bit value into Rd. Where the full 32 bits are required a
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workround is to use the movw and movt operations.
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