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https://github.com/drasko/codezero.git
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109 lines
2.0 KiB
ArmAsm
109 lines
2.0 KiB
ArmAsm
/*
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* Basic UART printing.
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*/
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#include INC_ARCH(asm.h)
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#include INC_GLUE(memlayout.h)
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#define UART_DATA_OFFSET 0x0
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.macro uart_address rx
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mrc p15, 0, \rx, c1, c0
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tst \rx, #1 @ MMU enabled?
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moveq \rx, #0x10000000
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orreq \rx, \rx, #0x001F0000
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orreq \rx, \rx, #0x00001000
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/* FIXME: This offset is incorrect */
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movne \rx, #0xf9000000 @#IO_AREA0_VADDR
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addne \rx, \rx, #PB926_UART0_VOFFSET @ UART0 page offset from
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@ virtual io area base.
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.endm
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.macro uart_send, ry, rx
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strb \ry, [\rx, #UART_DATA_OFFSET]
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.endm
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.macro uart_wait, ry, rx
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501:
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ldr \ry, [\rx, #0x18]
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tst \ry, #1 << 5
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bne 501b
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.endm
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.macro uart_busy, ry, rx
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501:
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ldr \ry, [\rx, #0x18]
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tst \ry, #1 << 3
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bne 501b
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.endm
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.text
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/*
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* Useful debugging routines
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*/
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BEGIN_PROC(printhex8)
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mov r1, #8
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b printhex
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BEGIN_PROC(printhex4)
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mov r1, #4
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b printhex
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BEGIN_PROC(printhex2)
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mov r1, #2
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printhex: adr r2, hexbuf
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add r3, r2, r1
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mov r1, #0
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strb r1, [r3]
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1: and r1, r0, #15
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mov r0, r0, lsr #4
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cmp r1, #10
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addlt r1, r1, #'0'
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addge r1, r1, #'a' - 10
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strb r1, [r3, #-1]!
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teq r3, r2
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bne 1b
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mov r0, r2
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b printascii
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.ltorg
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.align
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@ vmem-linked image has strings in vmem addresses. This replaces
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@ the reference with corresponding physical address. Note this
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@ won't work if memory offsets aren't clear cut values for
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@ orr'ing and bic'ing. rm = mmu bits rs = string address.
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.macro get_straddr rs, rm
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mrc p15, 0, \rm, c1, c0 @ Get MMU bits.
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tst \rm, #1 @ MMU enabled?
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biceq \rs, \rs, #KERNEL_AREA_START @ Clear Virtual mem offset.
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orreq \rs, \rs, #PHYS_ADDR_BASE @ Add Phy mem offset.
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.endm
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BEGIN_PROC(printascii)
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get_straddr r0, r1
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uart_address r3
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b 2f
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1: uart_wait r2, r3
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uart_send r1, r3
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uart_busy r2, r3
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teq r1, #'\n'
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moveq r1, #'\r'
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beq 1b
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2: teq r0, #0
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ldrneb r1, [r0], #1
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teqne r1, #0
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bne 1b
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mov pc, lr
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END_PROC(printascii)
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BEGIN_PROC(printch)
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uart_address r3
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mov r1, r0
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mov r0, #0
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b 1b
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hexbuf: .space 16
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