mirror of
https://github.com/garrettsworkshop/ROMBUSDriver.git
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50 lines
805 B
ArmAsm
50 lines
805 B
ArmAsm
.global spi_delay
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.global _reg_write16
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.global _reg_write8
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.global smear8to32
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* delay calling convention
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* D0 - iterations
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spi_delay:
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subq.w #1, %D0
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bne.b spi_delay
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rts
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* reg_write calling convention
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* A0 - address
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* D0 - data (clobbered)
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* D1 - clobbered
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_reg_write8:
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move.l %A0, %D1
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andi.l #0xFFFFFF00, %D1
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andi.l #0x000000FF, %D0
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or %D1, %D0
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movea %D0, %A0
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move.l (%A0), %D0
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rts
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_reg_write16:
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move.l %A0, %D1
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andi.l #0xFFFF0000, %D1
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andi.l #0x0000FFFF, %D0
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or %D1, %D0
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movea %D0, %A0
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move.l (%A0), %D0
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rts
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* smear8to32 calling convention
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* D0 - data in/out
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smear8to32:
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andi.l #0xFF, %D0
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move.l %D0, %D1
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lsl.w #8, %D1
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or.w %D1, %D0
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lsl.w #8, %D1
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or.w %D1, %D0
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lsl.w #8, %D1
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or.w %D1, %D0
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rts
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