2024-07-14 16:48:36 +00:00
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;; File: com.inc
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2024-07-18 10:36:43 +00:00
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;;
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;; Usefull links:
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;; - <PC16550D datasheet at https://www.scs.stanford.edu/10wi-cs140/pintos/specs/pc16550d.pdf>
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2024-07-14 16:48:36 +00:00
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2024-07-18 10:36:43 +00:00
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COM1 = 0x3F8
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COM2 = 0x2F8
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COM3 = 0x3E8
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COM4 = 0x2E8
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2024-07-21 16:14:38 +00:00
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NCOM = 4
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2024-07-18 10:36:43 +00:00
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UART8250_RBR = 0x0
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UART8250_THR = 0x0
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UART8250_IER = 0x1
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UART8250_IIR = 0x2
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UART8250_FCR = 0x2
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UART8250_LCR = 0x3
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UART8250_MCR = 0x4
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UART8250_LSR = 0x5
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UART8250_MSR = 0x6
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UART8250_SCR = 0x7
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; DLAB = 1
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UART8250_DLL = 0x0
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UART8250_DLH = 0x1
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2024-07-17 07:41:36 +00:00
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2024-07-18 09:48:35 +00:00
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com_init:
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2024-07-21 16:14:38 +00:00
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mov ax, COM1
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call com_probe
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or eax, eax
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jnz @f
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mov esi, szMsgCom1Found
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call klog
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@@:
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mov ax, COM2
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call com_probe
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or eax, eax
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jnz @f
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mov esi, szMsgCom2Found
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call klog
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@@:
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mov ax, COM3
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call com_probe
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or eax, eax
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jnz @f
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mov esi, szMsgCom3Found
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call klog
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@@:
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mov ax, COM4
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call com_probe
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or eax, eax
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jnz @f
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mov esi, szMsgCom4Found
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call klog
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@@:
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2024-07-18 09:48:35 +00:00
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ret
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2024-07-21 16:14:38 +00:00
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;; Function: com_probe
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2024-07-14 16:48:36 +00:00
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com_probe:
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2024-07-21 16:14:38 +00:00
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mov dx, ax
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add dx, UART8250_LCR
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xor al, al
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out dx, al
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dec dx
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out dx, al
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xor ecx, ecx
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@@:
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inc ecx
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cmp ecx, 100
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jbe @b
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in al, dx
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and al, 0x38
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or al, al
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jz @f
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mov eax, 1
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ret
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@@:
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xor eax, eax
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2024-07-14 16:48:36 +00:00
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ret
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2024-07-14 20:39:48 +00:00
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2024-07-18 10:36:43 +00:00
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com_irq1:
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2024-07-18 09:48:35 +00:00
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pusha
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popa
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2024-07-14 20:39:48 +00:00
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iret
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2024-07-17 07:41:36 +00:00
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2024-07-18 10:36:43 +00:00
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com_irq2:
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pusha
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popa
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iret
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2024-07-19 07:53:03 +00:00
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2024-07-21 16:14:38 +00:00
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com_open:
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ret
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com_close:
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ret
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com_read:
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ret
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com_write:
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ret
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com_ioctl:
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ret
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com_select:
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ret
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com_stop:
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ret
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com_mmap:
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ret
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com_reset:
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ret
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uCom1Lock dd 0
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uCom2Lock dd 0
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uComActive db 0
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szMsgCom1Found db "COM: com1 found", 0
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szMsgCom2Found db "COM: com2 found", 0
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szMsgCom3Found db "COM: com3 found", 0
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szMsgCom4Found db "COM: com4 found", 0
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2024-07-19 07:53:03 +00:00
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com_device:
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db 'com', 0, 0, 0, 0, 0
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dd com_init
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2024-07-21 16:14:38 +00:00
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com_cdevsw:
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dd com_open
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dd com_close
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dd com_read
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dd com_write
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dd com_ioctl
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dd com_select
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dd com_stop
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dd com_mmap
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dd com_reset
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