188 lines
3.4 KiB
ArmAsm
188 lines
3.4 KiB
ArmAsm
| file: boot.s
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| author: chapuni(GBA02750@niftyserve.or.jp)
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|.offset $100000
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|_header:: ds.l 8
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|_image::
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.global _header
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.global _image
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_header=0x100000 | まずは、このアドレスに
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_image=_header+(8*4) | コアをロードします。
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.global _bootufs
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.text
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top:
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jra entry:S
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.ascii "SHARP/"
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.ascii "X68030"
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.word 0x8199,0x94e6,0x82ea,0x82bd
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.word 0x8e9e,0x82c9,0x82cd,0x8cbb
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.word 0x8ec0,0x93a6,0x94f0,0x8149
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| 2400(もしくは$3F0000)
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| d4 にはすでに SCSI ID が入っている
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| ここから jmp まではリロケータブルに書かねばならない。
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entry:
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lea _edata:l,a0 | clear out BSS
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movl #_end-4,d0 | (must be <= 256 kB)
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subl #_edata,d0
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lsrl #2,d0
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1: clrl a0@+
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dbra d0,1b
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lea top:l,a1 | 0x3F0000 にスタックポインタを
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lea a1@,sp | 設定する。だから :l が付いてないとダメ
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moveq #1,d5 | 512bytes/sec
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moveq #8192/512,d3 | 読み込める最大サイズ
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moveq #0x40,d2 | いわゆる決め打ち(sd*a のみ)
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moveq #0x21,d1 | read
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moveq #0xFFFFFFF5,d0 | SCSI
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trap #15
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movel d4,_ID:l
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| テキストパレットの初期化
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moveq #7,d3
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moveq #0,d1
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initpalet:
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moveq #0,d2
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moveq #0x14,d0 |TPALET2
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trap #15
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addqw #1,d1
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movel #0xFFFF,d2
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moveq #0x14,d0 |TPALET2
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trap #15
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addqw #1,d1
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dbra d3,initpalet
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jmp _bootufs:l | 0x3Fxxxx に飛んでゆく
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| int RAW_READ(void *buf, int pos, size_t length);
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| .offset 16
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|raw_read_buf: ds.l 1
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|raw_read_pos: ds.l 1
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|raw_read_len: ds.l 1
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| .text
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raw_read_buf= 4+(4*11)
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raw_read_pos= raw_read_buf+4
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raw_read_len= raw_read_buf+8
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.global _RAW_READ
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_RAW_READ:
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moveml a2-a6/d2-d7,sp@-
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movel _ID:l,d4
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moveq #1,d5 | 512bytes/sec
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movel sp@(raw_read_buf),a1
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movel sp@(raw_read_pos),d2
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movel sp@(raw_read_len),d3
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addl #511,d3
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moveq #9,d1
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lsrl d1,d2
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lsrl d1,d3
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addl #0x40,d2
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moveq #0x21,d1
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moveq #0xF5-0x100,d0
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trap #15
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moveml sp@+,a2-a6/d2-d7
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rts
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.global _JISSFT
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_JISSFT:
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movel sp@(4),d1
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moveq #0xFFFFFFA1,d0
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trap #15
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rts
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.global _B_SFTSNS
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_B_SFTSNS:
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moveq #0x02,d0
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trap #15
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rts
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.global _B_KEYINP
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_B_KEYINP:
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moveq #0x00,d0
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trap #15
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rts
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.global _B_PUTC
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_B_PUTC:
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movel sp@(4),d1
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moveq #0x20,d0
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trap #15
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rts
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.global _B_PRINT
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_B_PRINT:
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movel sp@(4),a1
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moveq #0x21,d0
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trap #15
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rts
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.global _B_COLOR
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_B_COLOR:
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movel sp@(4),d1
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moveq #0x22,d0
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trap #15
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rts
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.global _B_LOCATE
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_B_LOCATE:
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movel d2,sp@-
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movel sp@(8),d1
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movel sp@(12),d2
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moveq #0x23,d0
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trap #15
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movel sp@+,d2
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rts
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.global _B_CLR_ST
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_B_CLR_ST:
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movel sp@(4),d1
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moveq #0x2A,d0
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trap #15
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rts
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|IOCS SYS_STAT $AC
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|入力 d1.l=0 のとき d0.l に以下の値
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| bit0～7 0:68000, 1:68010, 2:68020, 3:68030
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| bit14 0:MMUなし, 1:MMUあり
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| bit15 0:FPCPなし, 1:FPCPあり
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| bit16～31 クロックスピード
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| X68000 の IOCS には $AC はないのでエラーになりますが、Xellent30 の場合は
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|起動時に SRAM で組み込んでくれます。
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.global _SYS_STAT
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_SYS_STAT:
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movel sp@(4),d1
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moveq #0xAC-0x100,d0
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trap #15
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rts
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.global _getcpu
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_getcpu:
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movl #0x200,d0 | data freeze bit
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movc d0,cacr | only exists on 68030
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movc cacr,d0 | read it back
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tstl d0 | zero?
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jeq Lnot68030 | yes, we have 68020/68040
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movq #3,d0 | 68030
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rts
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Lnot68030:
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bset #31,d0 | data cache enable bit
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movc d0,cacr | only exists on 68040
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movc cacr,d0 | read it back
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tstl d0 | zero?
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beq Lis68020 | yes, we have 68020
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moveq #0,d0 | now turn it back off
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movec d0,cacr | before we access any data
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movq #4,d0 | 68040
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rts
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Lis68020:
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movq #2,d0 | 68020
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rts
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.comm _ID,4
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.end
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