21 lines
620 B
ArmAsm
21 lines
620 B
ArmAsm
global outb
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; out b - send a byte to an I/O port
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; stack: [esp + 8] the data byte
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; [esp + 4] the I/O port
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; [esp ] return address
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outb:
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mov al, [esp + 8]
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mov dx, [esp + 4] ; move the address into dx
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out dx, al ; send the data to the I/O port
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ret ; return to the calling function
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global inb
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; inb - returns a byte from the given I/O port
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; stack: [esp + 4] The address of the I/O port
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; [esp ] The return address
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inb:
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mov dx, [esp + 4] ; move the address of the I/O port to the dx register
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in al, dx ; read a byte from the I/O port and store it in the al register
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ret ; return the read byte
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