5b69777647
GNU as has "la %r4,8(%r3)" as an alias for "addi %r4,%r3,8", meaning to load the address of the thing at 8(%r3). Our 'la', now 'li32', makes an addis/ori pair to load an immediate 32-bit value. For example, "li32 r4,23456789" loads a big number.
53 lines
775 B
ArmAsm
53 lines
775 B
ArmAsm
#
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! $Source: /cvsroot/tack/Ack/plat/linux386/libsys/_syscall.s,v $
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! $State: Exp $
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! $Revision: 1.1 $
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! Declare segments (the order is important).
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.sect .text
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.sect .rom
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.sect .data
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.sect .bss
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.sect .text
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EINVAL = 22
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#define IFFALSE 4
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#define IFTRUE 12
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#define ALWAYS 20
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#define LT 0
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#define GT 1
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#define EQ 2
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#define OV 3
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! Perform a Linux system call.
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.define __syscall
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__syscall:
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lwz r0, 0(sp)
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lwz r3, 4(sp)
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lwz r4, 8(sp)
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lwz r5, 12(sp)
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sc 0
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bclr IFFALSE, OV, 0
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! On error, r3 contains the errno.
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! It just so happens that errnos 1-34 are the same in Linux as in ACK.
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cmpi cr0, 0, r3, 1
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bc IFTRUE, LT, 2f
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cmpi cr0, 0, r3, 34
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bc IFTRUE, GT, 2f
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3:
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li32 r4, _errno
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stw r3, 0(r4)
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addi r3, r0, -1
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bclr ALWAYS, 0, 0
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2:
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addi r3, r0, EINVAL
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b 3b
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