megadrive_test1
changeset 0:909c22dc18d2
initial commit
| author | John Tsiombikas <nuclear@member.fsf.org> |
|---|---|
| date | Mon, 30 Jan 2017 08:21:53 +0200 |
| parents | |
| children | 9e7f64c4fe7a |
| files | .hgignore Makefile megadrive.ldscript src/intr.s src/main.s src/romhdr.S src/startup.s |
| diffstat | 7 files changed, 213 insertions(+), 0 deletions(-) [+] |
line diff
1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000 1.2 +++ b/.hgignore Mon Jan 30 08:21:53 2017 +0200 1.3 @@ -0,0 +1,6 @@ 1.4 +\.o$ 1.5 +\.d$ 1.6 +\.swp$ 1.7 +\.elf$ 1.8 +\.bin$ 1.9 +link\.map$
2.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000 2.2 +++ b/Makefile Mon Jan 30 08:21:53 2017 +0200 2.3 @@ -0,0 +1,32 @@ 2.4 +asrc = $(wildcard src/*.s) 2.5 +aSsrc = $(wildcard src/*.S) 2.6 +obj = $(asrc:.s=.o) $(aSsrc:.S=.o) 2.7 + 2.8 +name = test1 2.9 +elf = $(name).elf 2.10 +bin = $(name).bin 2.11 + 2.12 +warn = -pedantic -Wall 2.13 +dbg = -g 2.14 +def = -DGAMENAME=\"testgame\" -DVERSTR=\"01\" 2.15 + 2.16 +tool_prefix = m68k-linux-gnu- 2.17 + 2.18 +CC = $(tool_prefix)gcc 2.19 +AS = $(tool_prefix)as 2.20 +LD = $(tool_prefix)ld 2.21 +OBJCOPY = $(tool_prefix)objcopy 2.22 + 2.23 +CFLAGS = -m68000 -nostdinc -fno-builtin $(warn) $(dbg) $(opt) $(def) 2.24 +ASFLAGS = -m68000 2.25 +LDFLAGS = -T megadrive.ldscript -print-gc-sections 2.26 + 2.27 +$(bin): $(elf) 2.28 + $(OBJCOPY) -O binary $< $@ 2.29 + 2.30 +$(elf): $(obj) 2.31 + $(LD) -o $@ $(LDFLAGS) $(obj) -Map link.map 2.32 + 2.33 +.PHONY: clean 2.34 +clean: 2.35 + rm -f $(obj) $(elf) $(bin)
3.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000 3.2 +++ b/megadrive.ldscript Mon Jan 30 08:21:53 2017 +0200 3.3 @@ -0,0 +1,44 @@ 3.4 +OUTPUT_ARCH(m68k) 3.5 + 3.6 +MEMORY 3.7 +{ 3.8 + rom : ORIGIN = 0x00000000, LENGTH = 0x00a00000 3.9 + ram : ORIGIN = 0x00ff0000, LENGTH = 0x00010000 3.10 +} 3.11 + 3.12 +PROVIDE (_stacktop = 0x01000000); 3.13 + 3.14 +SECTIONS { 3.15 + /* ---- start of ROM ---- */ 3.16 + /* .vect section is used to place the m68k exception vectors at the 3.17 + * beginning of the address space 3.18 + */ 3.19 + .vect : { KEEP (* (.vect)); } >rom 3.20 + /* .romhdr section is used to place the SEGA ROM header at 0x100 */ 3.21 + . = 0x100; 3.22 + .romhdr : { KEEP (* (.romhdr)); } >rom 3.23 + .text : { * (.text); } >rom 3.24 + .rodata : { * (.rodata); } >rom 3.25 + 3.26 + /* place the load address of the .data section after .rodata */ 3.27 + _data_lma = .; 3.28 + _rom_end = _data_lma + _data_size; 3.29 + 3.30 + /* ---- start of RAM ---- */ 3.31 + . = 0xff0000; 3.32 + /* place the .data section at the start of RAM */ 3.33 + .data : AT (_data_lma) { 3.34 + _data_start = .; 3.35 + * (.data); 3.36 + _data_end = .; 3.37 + } >ram 3.38 + _data_size = SIZEOF(.data); 3.39 + 3.40 + /* place the .bss section at the end */ 3.41 + .bss : { 3.42 + _bss_start = .; 3.43 + * (.bss); 3.44 + _bss_end = .; 3.45 + } >ram 3.46 + _bss_size = SIZEOF(.bss); 3.47 +}
4.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000 4.2 +++ b/src/intr.s Mon Jan 30 08:21:53 2017 +0200 4.3 @@ -0,0 +1,82 @@ 4.4 +| the following will go into the .vect section which will be placed at the very 4.5 +| begining of the binary at address 0 by the linker (see lnkscript). 4.6 + .section .vect,"a" 4.7 + .extern start 4.8 +| exception vectors 4.9 + .long _stacktop | 00 reset - initial SSP 4.10 + .long start | 01 reset - initial PC 4.11 + .long intr_fatal | 02 bus error 4.12 + .long intr_fatal | 03 address error 4.13 + .long intr_fatal | 04 illegal instruction 4.14 + .long intr_fatal | 05 zero divide 4.15 + .long intr_fatal | 06 chk instruction 4.16 + .long intr_fatal | 07 trapv instruction 4.17 + .long intr_fatal | 08 privilege violation 4.18 + .long intr_fatal | 09 trace 4.19 + .long intr_fatal | 0a line 1010 emulator 4.20 + .long intr_fatal | 0b line 1111 emulator 4.21 + .long intr_fatal | 0c reserved 4.22 + .long intr_fatal | 0d reserved 4.23 + .long intr_fatal | 0e format error (mc68010 only) 4.24 + .long intr_fatal | 0f uninitialized interrupt vector 4.25 + .long intr_fatal | 10 \ 4.26 + .long intr_fatal | 11 | 4.27 + .long intr_fatal | 12 | 4.28 + .long intr_fatal | 13 > reserved 4.29 + .long intr_fatal | 14 | 4.30 + .long intr_fatal | 15 | 4.31 + .long intr_fatal | 16 | 4.32 + .long intr_fatal | 17 / 4.33 + .long intr_fatal | 18 spurious interrupt 4.34 + .long intr_fatal | 19 level 1 interrupt 4.35 + .long intr_fatal | 1a level 2 interrupt 4.36 + .long intr_fatal | 1b level 3 interrupt 4.37 + .long intr_hblank | 1c level 4 interrupt (hblank in the mega drive) 4.38 + .long intr_fatal | 1d level 5 interrupt 4.39 + .long intr_vblank | 1e level 6 interrupt (vblank in the mega drive) 4.40 + .long intr_fatal | 1f level 7 interrupt 4.41 + .long intr_fatal | 20 trap 0 4.42 + .long intr_fatal | 21 trap 1 4.43 + .long intr_fatal | 22 trap 2 4.44 + .long intr_fatal | 23 trap 3 4.45 + .long intr_fatal | 24 trap 4 4.46 + .long intr_fatal | 25 trap 5 4.47 + .long intr_fatal | 26 trap 6 4.48 + .long intr_fatal | 27 trap 7 4.49 + .long intr_fatal | 28 trap 8 4.50 + .long intr_fatal | 29 trap 9 4.51 + .long intr_fatal | 2a trap a 4.52 + .long intr_fatal | 2b trap b 4.53 + .long intr_fatal | 2c trap c 4.54 + .long intr_fatal | 2d trap d 4.55 + .long intr_fatal | 2e trap e 4.56 + .long intr_fatal | 2f trap f 4.57 + .long intr_fatal | 30 \ 4.58 + .long intr_fatal | 31 | 4.59 + .long intr_fatal | 32 | 4.60 + .long intr_fatal | 33 | 4.61 + .long intr_fatal | 34 | 4.62 + .long intr_fatal | 35 | 4.63 + .long intr_fatal | 36 | 4.64 + .long intr_fatal | 37 | 4.65 + .long intr_fatal | 38 > reserved 4.66 + .long intr_fatal | 39 | 4.67 + .long intr_fatal | 3a | 4.68 + .long intr_fatal | 3b | 4.69 + .long intr_fatal | 3c | 4.70 + .long intr_fatal | 3d | 4.71 + .long intr_fatal | 3e | 4.72 + .long intr_fatal | 3f / 4.73 + 4.74 +| from here on we continue in the regular .text section since we don't care 4.75 +| where this code ends up. 4.76 + .text 4.77 +| interrupt handlers 4.78 +intr_fatal: 4.79 + stop #0x2700 4.80 + 4.81 +| TODO hblank/vblank code 4.82 +intr_hblank: 4.83 + rte 4.84 +intr_vblank: 4.85 + rte
5.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000 5.2 +++ b/src/main.s Mon Jan 30 08:21:53 2017 +0200 5.3 @@ -0,0 +1,4 @@ 5.4 + .text 5.5 + .global main 5.6 +main: 5.7 + rts
6.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000 6.2 +++ b/src/romhdr.S Mon Jan 30 08:21:53 2017 +0200 6.3 @@ -0,0 +1,37 @@ 6.4 +| the following will go into the custom .romhdr section which will be placed at 6.5 +| address 100 of the binary by the linker (see lnkscript). 6.6 + .section .romhdr,"a" 6.7 + 6.8 +#ifndef GAMENAME 6.9 +#define GAMENAME "unnamed" 6.10 +#endif 6.11 +#ifndef VERSTR 6.12 +#define VERSTR "00" 6.13 +#endif 6.14 + 6.15 + .ascii "SEGA MEGA DRIVE (C)MINDLAPSE2017" 6.16 +hdr_game_dom: 6.17 + .ascii GAMENAME 6.18 +hdr_game_dom_end: 6.19 + .fill 48 - (hdr_game_dom_end - hdr_game_dom),1,32 | pad to 48 bytes with spaces 6.20 +hdr_game_int: 6.21 + .ascii GAMENAME 6.22 +hdr_game_int_end: 6.23 + .fill 48 - (hdr_game_int_end - hdr_game_int),1,32 | pad to 48 bytes with spaces 6.24 + .ascii "GM" | it's a game (who cares what it is?) 6.25 + .ascii "0000000-" | product code 6.26 + .ascii VERSTR | version string 6.27 + .short 0 | checksum 6.28 + .ascii "J " | I/O support (joypad) 6.29 + .long 0 | start address of ROM 6.30 + .long _rom_end | last address of ROM 6.31 + .long 0xff0000 | start address of RAM 6.32 + .long 0xffffff | last address of RAM 6.33 + .long 0 | SRAM enabled(?) 6.34 + .long 0 | ??? 6.35 + .long 0 | start address of SRAM 6.36 + .long 0 | last address of SRAM 6.37 + .long 0 | ??? 6.38 + .long 0 | ??? 6.39 + .fill 40,1,32 | notes (fill with spaces for now TODO) 6.40 + .ascii "JUE " | country codes