xv6-cs450/trapasm.S

40 lines
678 B
ArmAsm

.text
.globl trap
.globl trapret1
.globl alltraps
.set SEG_KDATA_SEL, 0x10 # selector for SEG_KDATA
# vectors.S sends all traps here.
alltraps:
# Build trap frame.
pushl %ds
pushl %es
pushal
# Set up data segments.
movl $SEG_KDATA_SEL, %eax
movw %ax,%ds
movw %ax,%es
# Call trap(tf), where tf=%esp
pushl %esp
call trap
addl $4, %esp
# Return falls through to trapret...
.globl trapret
trapret:
popal
popl %es
popl %ds
addl $0x8, %esp # trapno and errcode
iret
# A forked process switches to user mode by calling
# forkret1(tf), where tf is the trap frame to use.
.globl forkret1
forkret1:
movl 4(%esp), %esp
jmp trapret