103 lines
2.2 KiB
ArmAsm
103 lines
2.2 KiB
ArmAsm
jmp entry
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puts:
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; Write string to console
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; r2: [IN] *const u8 String pointer
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; r3: [IN] usize String length
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li8 r1, 0x1 ; Write syscall
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brc r2, r3, 2 ; Copy parameters
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li8 r2, 0x1 ; STDOUT
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eca
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jal r0, r31, 0
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gets:
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; Read string until end of buffer or LF
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; r2: [IN] *mut u8 Buffer
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; r3: [IN] usize Buffer length
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; Register allocations:
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; r33: *mut u8 Buffer end
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; r34: u8 Immediate char
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; r35: u8 Const [0x0A = LF]
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li8 r35, 0x0A
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add64 r33, r2, r3
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; Setup syscall
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li8 r2, 0x1 ; Stdin
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cp r3, r2
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li8 r4, 0x1 ; Read one char
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jeq r3, r33, end
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loop:
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li8 r1, 0x1 ; Read syscall
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eca
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addi64 r3, r3, 1
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ld r34, r3, 0, 1
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jeq r34, r35, end
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jne r3, r33, loop
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end:
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; Set copied amount
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sub64 r1, r33, r3
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addi64 r1, r1, -1
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jal r0, r31, 0
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alloc_pages:
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; Allocate pages
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; r1: [OUT] *mut u8 Pointer to page
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; r2: [IN] u16 Page count
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muli16 r3, r2, 4096 ; page count
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li8 r1, 0x9 ; mmap syscall
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li8 r2, 0x0 ; no address set, kernel chosen
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li8 r4, 0x2 ; PROT_WRITE
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li8 r5, 0x20 ; MAP_ANONYMOUS
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li64 r6, -1 ; Doesn't map file
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li8 r7, 0x0 ; Doesn't map file
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eca
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jal r0, r31, 0
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entry:
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; Program entrypoint
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; Register allocations:
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; r32: *mut u8 Buffer
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; r36: usize Read buffer length
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; Allocate one page (4096 KiB)
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li8 r2, 1
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jal r31, r0, alloc_pages
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cp r32, r1
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; Print message
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lra16 r2, r0, enter_your_name
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li8 r3, 17
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jal r31, r0, puts
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; Read name
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cp r2, r32
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li16 r3, 4096
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jal r31, r0, gets
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cp r36, r1
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; Print your name is
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lra16 r2, r0, your_name_is
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li8 r3, 15
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jal r31, r0, puts
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; And now print the name
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cp r2, r32
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cp r3, r36
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jal r31, r0, puts
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tx
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enter_your_name:
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.db "Enter your name: "
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your_name_is:
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.db "\nYour name is: " |