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112 lines
2.7 KiB
ArmAsm
112 lines
2.7 KiB
ArmAsm
;
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; Ullrich von Bassewitz, 2003-04-15
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;
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; Common functions of the serial drivers
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;
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.import return0
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.importzp ptr1
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.condes ser_irq, 2 ; Export as IRQ handler
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.include "ser-kernel.inc"
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.include "ser-error.inc"
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;----------------------------------------------------------------------------
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; Variables
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.bss
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_ser_drv: .res 2 ; Pointer to driver
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; Jump table for the driver functions.
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.data
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ser_vectors:
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ser_install: jmp return0
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ser_uninstall: jmp return0
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ser_open: jmp return0
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ser_close: jmp return0
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ser_get: jmp return0
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ser_put: jmp return0
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ser_status: jmp return0
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ser_ioctl: jmp return0
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ser_irq: .byte $60, $00, $00 ; RTS plus two dummy bytes
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; Driver header signature
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.rodata
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ser_sig: .byte $73, $65, $72, SER_API_VERSION ; "ser", version
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;----------------------------------------------------------------------------
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; unsigned char __fastcall__ ser_install (void* driver);
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; /* Install the driver once it is loaded */
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_ser_install:
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sta _ser_drv
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sta ptr1
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stx _ser_drv+1
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stx ptr1+1
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; Check the driver signature
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ldy #.sizeof(ser_sig)-1
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@L0: lda (ptr1),y
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cmp ser_sig,y
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bne inv_drv
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dey
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bpl @L0
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; Copy the jump vectors
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ldy #SER_HDR::JUMPTAB
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ldx #0
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@L1: inx ; Skip the JMP opcode
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jsr copy ; Copy one byte
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jsr copy ; Copy one byte
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cpy #(SER_HDR::JUMPTAB + .sizeof(SER_HDR::JUMPTAB))
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bne @L1
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jsr ser_install ; Call driver install routine
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ldy ser_irq+2 ; Check high byte of IRQ vector
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beq @L2 ; Jump if vector invalid
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ldy #$4C ; Jump opcode
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sty ser_irq ; Activate IRQ routine
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@L2: rts
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; Driver signature invalid
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inv_drv:
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lda #SER_ERR_INV_DRIVER
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ldx #0
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rts
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; Copy one byte from the jump vectors
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copy: lda (ptr1),y
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sta ser_vectors,x
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iny
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inx
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rts
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;----------------------------------------------------------------------------
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; unsigned char __fastcall__ ser_uninstall (void);
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; /* Uninstall the currently loaded driver and return an error code.
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; * Note: This call does not free allocated memory.
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; */
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_ser_uninstall:
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jsr ser_uninstall ; Call driver routine
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lda #$60 ; RTS opcode
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sta ser_irq ; Disable IRQ entry point
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lda #0
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sta _ser_drv
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sta _ser_drv+1 ; Clear the driver pointer
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tax
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rts ; Return zero
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