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recipes/pcat: first steps into 8086!
2020-06-13 04:01:24 +10:00
H@ ORG ! 0x7c00 BIN( ! ( BIOS loads boot bin at 0x7c00 )
8086asm: tidy up a bit
2020-06-14 06:21:56 +10:00
JMPs, L1 FWRs ( start )
recipes/pcat: now tested on real hardware!
2020-06-14 01:47:32 +10:00
ORG @ 0x25 + HERE ! ( bypass BPB )
recipes/pcat: first steps into 8086!
2020-06-13 04:01:24 +10:00
L1 FSET ( start )
pcat: use a far jump to boot into the OS Unless I misunderstood, this is supposed to set CS. This would make all SREG have the same value. This allows us to remove BIN( offset from os.bin. I've tried booting to offset 0, but it didn't seem to work. Let's settle for 0x8000. 512kb of system RAM is way more than we need anyways.
2020-06-14 10:06:51 +10:00
CLI, CLD, AX 0x800 MOVxi, DS AX MOVsx, ES AX MOVsx,
8086asm: clarify operands and fix stupidities
2020-06-14 07:58:42 +10:00
SS AX MOVsx, SP 0xffff MOVxi, STI,
AH 2 MOVri, DX 0 MOVxi, CH 0 MOVri, CL 2 MOVri, AL 1 MOVri,
pcat: use a far jump to boot into the OS Unless I misunderstood, this is supposed to set CS. This would make all SREG have the same value. This allows us to remove BIN( offset from os.bin. I've tried booting to offset 0, but it didn't seem to work. Let's settle for 0x8000. 512kb of system RAM is way more than we need anyways.
2020-06-14 10:06:51 +10:00
BX 0 MOVxi, 0x13 INT, ( read 2nd sector of boot floppy )
0x800 0 JMPf,
recipes/pcat: now tested on real hardware!
2020-06-14 01:47:32 +10:00
ORG @ 0x1fe + HERE ! 0x55 A, 0xaa A,