GSP COFF Assembler, Version 2.00, 87.300 Sun Oct 18 03:03:04 2026 (c) Copyright 1985, 1987, Texas Instruments Inc. PAGE 1 0001 ; retprobe.asm -- MINIMAL test of the DI return-PC tram 0002 ; 0003 ; Installs `entry` on the DI RAM stub (00000DB0h). `en 0004 ; interrupt frame's saved PC with `ret_hook` and runs t 0005 ; `ret_hook` bumps a marker and returns to the saved PC 0006 ; NOT preserve registers, so TCP liveness tells us whet 0007 ; itself is sound. Scratch is in the payload's own pag 0008 ; 0009 ; Linked at bit 01840000h by dwt/visual/build.sh. 0010 0011 00000000 .text 0012 00000000 _start: 0013 00000000 01E0 pushst 0014 00000010 0360 dint 0015 00000020 0540 setf 32, 0, 0 0016 00000030 09E0 movi entry, a0, L 00000040 00000160' 0017 00000060 0580 move a0, @00000DC0h, 0 00000070 00000DC0 0018 00000090 0550 setf 16, 0, 0 0019 000000A0 09E0 movi 0C080h, a0, L 000000B0 0000C080 0020 000000D0 0580 move a0, @00000DB0h, 0 000000E0 00000DB0 0021 00000100 4400 sub a0, a0 0022 00000110 0580 move a0, @01840800h, 0 ; marker 00000120 01840800 0023 00000140 01C0 popst 0024 00000150 0960 rets 0025 0026 00000160 entry: 0027 00000160 0780 move a0, @01840810h, 1 00000170 01840810 0028 00000190 0740 setf 32, 0, 1 0029 000001A0 B7E0 move *sp(020h), a0, 1 000001B0 0020 0030 000001C0 0780 move a0, @01840804h, 1 ; orig_pc 000001D0 01840804 0031 000001F0 09E0 movi ret_hook, a0, L 00000200 000002A0' 0032 00000220 B20F move a0, *sp(020h), 1 00000230 0020 0033 00000240 07A0 move @01840810h, a0, 1 00000250 01840810 0034 00000270 C080 jauc 3F7146D0h 00000280 3F7146D0 0035 0036 000002A0 ret_hook: 0037 000002A0 05A0 move @01840800h, a0, 0 000002B0 01840800 0038 000002D0 1020 inc a0 0039 000002E0 0580 move a0, @01840800h, 0 000002F0 01840800 0040 00000310 0740 setf 32, 0, 1 0041 00000320 07A0 move @01840804h, a0, 1 ; orig_pc 00000330 01840804 GSP COFF Assembler, Version 2.00, 87.300 Sun Oct 18 03:03:04 2026 (c) Copyright 1985, 1987, Texas Instruments Inc. PAGE 2 0042 00000350 A20F move a0, -*sp, 1 0043 00000360 0180 getst a0 ; (clobbers a0 on purpose) 0044 00000370 A20F move a0, -*sp, 1 0045 00000380 01C0 popst 0046 00000390 0960 rets 0047 .end No Errors, No Warnings