171 lines
3.6 KiB
ArmAsm
171 lines
3.6 KiB
ArmAsm
.export _init, _nmi_int, _irq_int
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.include "zeropage.inc"
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.autoimport
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.segment "VECTORS"
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.addr _nmi_int ; NMI vector
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.addr _init ; Reset vector
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.addr _irq_int ; IRQ/BRK vector
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SD_CONTROLLER = $e000
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SD_CMD = SD_CONTROLLER
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SD_ARG = SD_CONTROLLER + $4
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SD_DATA = SD_ARG
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SD_FIFO_0 = SD_CONTROLLER + $8
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SD_FIFO_2 = SD_CONTROLLER + $C
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SD_PHY = SD_CONTROLLER + $10
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SD_PHY_CLKDIV = SD_PHY
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SD_PHY_CLKCTRL = SD_PHY + $1
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SD_PHY_SAMP_VOLT = SD_PHY + $2
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SD_PHY_BLKSIZ = SD_PHY + $3
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SD_DMA_BASE = SD_CONTROLLER + $28
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SD_DMA_STAT_CTRL = SD_CONTROLLER + $2C
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SDIOCLK_100KHZ = $FC
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SPEED_512B = $09
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.zeropage
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rca: .res 4
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.code
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_nmi_int:
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_irq_int:
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_init:
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ldx #$ff
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txs
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cld
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lda #<(__STACKSTART__ + __STACKSIZE__)
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sta sp
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lda #>(__STACKSTART__ + __STACKSIZE__)
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sta sp+1
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stz SD_PHY_CLKCTRL
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stz SD_PHY_SAMP_VOLT
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lda #SPEED_512B
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sta SD_PHY_BLKSIZ
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lda #SDIOCLK_100KHZ
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sta SD_PHY_CLKDIV
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@wait_clk: lda SD_PHY_CLKDIV
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cmp #SDIOCLK_100KHZ
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bne @wait_clk
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; send_goidle();
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jsr send_goidle
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; send_r1(8, 0x1aa);
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lda #$0
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sta sreg+1
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lda #$0
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sta sreg
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ldx #$01
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lda #$aa
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jsr pusheax
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lda #$08
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jsr send_r1
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@acmd41:
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; send_r1(55, 0x00);
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lda #$0
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sta sreg+1
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lda #$0
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sta sreg
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ldx #$00
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lda #$00
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jsr pusheax
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lda #55
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jsr send_r1
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; send_r1(41, 0x4000ff80);
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lda #$40
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sta sreg+1
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lda #$0
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sta sreg
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ldx #$ff
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lda #$80
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jsr pusheax
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lda #41
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jsr send_r1
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lda sreg+1
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bpl @acmd41
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; cmd 11
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; cmd 2
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; cmd 3
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@end:
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bra @end
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wait_busy: lda SD_CMD+$1
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bit #$40
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bne wait_busy
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rts
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; No arguments, no response
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; sends cmd0
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; also clears removed and error flags?
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send_goidle:
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stz SD_ARG+$3
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stz SD_ARG+$2
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stz SD_ARG+$1
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stz SD_ARG
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stz SD_CMD+$3
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lda #$04
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sta SD_CMD+$2
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lda #$80
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sta SD_CMD+$1
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lda #$40
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sta SD_CMD
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jsr wait_busy
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rts
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; Command in A
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; Arg on stack as 32 bits
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; returns the response in eax
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; (How can we signal a failure then?)
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send_r1:
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pha ; push command to stack
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jsr popeax
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PHA
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stx SD_ARG+$1
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lda sreg
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sta SD_ARG+$2
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lda sreg+1
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sta SD_ARG+$3
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pla
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sta SD_ARG ; lsb has to be the last written.
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lda #$81 ; This also clears error flag (only for acmd41?)
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sta SD_CMD+$1
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pla
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ora #$40
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sta SD_CMD
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jsr wait_busy
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lda SD_DATA + $3
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sta sreg+1
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lda SD_DATA + $2
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sta sreg
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ldx SD_DATA + $1
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lda SD_DATA
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rts |