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https://github.com/autc04/Retro68.git
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193 lines
4.4 KiB
ArmAsm
193 lines
4.4 KiB
ArmAsm
.global _start
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_start:
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# START Interrupt Vector Table [[
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jmp __PMSIZE-4
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jmp watchdog_init
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jmp interrupt_0
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jmp interrupt_1
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jmp interrupt_2
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jmp interrupt_3
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jmp interrupt_4
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jmp interrupt_5
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jmp interrupt_6
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jmp interrupt_7
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jmp interrupt_8
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jmp interrupt_9
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jmp interrupt_10
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jmp interrupt_11
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jmp interrupt_12
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jmp interrupt_13
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jmp interrupt_14
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jmp interrupt_15
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jmp interrupt_16
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jmp interrupt_17
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jmp interrupt_18
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jmp interrupt_19
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jmp interrupt_20
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jmp interrupt_21
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jmp interrupt_22
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jmp interrupt_23
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jmp interrupt_24
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jmp interrupt_25
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jmp interrupt_26
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jmp interrupt_27
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jmp interrupt_28
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jmp interrupt_29
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jmp interrupt_30
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jmp interrupt_31
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jmp __PMSIZE-8
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# ]] END Interrupt Vector Table
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codestart:
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jmp init
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.global _exithook
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_exithook: # Debugger uses '_exithook' at 0x90 to catch program exit
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return
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watchdog_init:
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ldk $r0,1
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init:
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ldk $sp,__RAMSIZE
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# Disable all interrupts
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ldk $r4,0x80
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sta.b 0x100e3,$r4
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# Initialize DATA by copying from program memory
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ldk.l $r4,__data_load_start
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ldk.l $r1,__data_load_end
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ldk.l $r2,0 # Will use __data after binutils patch
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jmp .dscopy
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.dsloop:
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# Copy PM[$r4] to RAM $r2
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lpmi.l $r3,$r4,0
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sti.l $r2,0,$r3
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add.l $r4,$r4,4
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add.l $r2,$r2,4
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.dscopy:
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cmp.l $r4,$r1
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jmpc lt,.dsloop
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# Zero BSS
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ldk.l $r4,_bss_start
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ldk.l $r2,_end
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sub.l $r2,$r2,$r4
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ldk.l $r1,0
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ldk $r3,32764
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1:
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cmp $r2,$r3
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jmpc lt,2f
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memset $r4,$r1,$r3
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add $r4,$r4,$r3
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sub $r2,$r2,$r3
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jmp 1b
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2:
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memset $r4,$r1,$r2
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sub.l $sp,$sp,24 # Space for the caller argument frame
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call main
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.equ EXITEXIT,0x1fffc
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.global _exit
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_exit:
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sta.l EXITEXIT,$r0 # simulator end of test
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jmp _exithook
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# Macro to construct the interrupt stub code.
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# it just saves r0, loads r0 with the int vector
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# and branches to interrupt_common.
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.macro inth i=0
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interrupt_\i:
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push $r0 # {
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lda $r0,(vector_table + 4 * \i)
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jmp interrupt_common
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.endm
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inth 0
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inth 1
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inth 2
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inth 3
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inth 4
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inth 5
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inth 6
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inth 7
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inth 8
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inth 9
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inth 10
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inth 11
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inth 12
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inth 13
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inth 14
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inth 15
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inth 16
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inth 17
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inth 18
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inth 19
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inth 20
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inth 21
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inth 22
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inth 23
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inth 24
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inth 25
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inth 26
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inth 27
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inth 28
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inth 29
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inth 30
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inth 31
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inth 32
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# On entry: r0, already saved, holds the handler function
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interrupt_common:
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push $r1 # {
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push $r2 # {
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push $r3 # {
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push $r4 # {
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push $r5 # {
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push $r6 # {
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push $r7 # {
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push $r8 # {
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push $r9 # {
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push $r10 # {
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push $r11 # {
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push $r12 # {
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push $cc # {
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calli $r0
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pop $cc # }
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pop $r12 # }
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pop $r11 # }
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pop $r10 # }
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pop $r9 # }
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pop $r8 # }
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pop $r7 # }
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pop $r6 # }
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pop $r5 # }
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pop $r4 # }
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pop $r3 # }
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pop $r2 # }
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pop $r1 # }
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pop $r0 # } matching push in interrupt_0-31 above
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reti
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# Null function for unassigned interrupt to point at
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.global nullvector
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nullvector:
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return
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.section .data
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.global vector_table
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vector_table:
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.rept 33
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.long nullvector
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.endr
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.section .text
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.global __gxx_personality_sj0
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__gxx_personality_sj0:
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