code wiki / _hdl_build / nx_emu_x86_farjmp_test.nx
nx_emu_x86_farjmp_test.nx
buildroot/runtime/_hdl_build/nx_emu_x86_farjmp_test.nx
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nx_emu_x86_farjmp_test.nx -- x86 full-system ladder R5 rung-5: PROTECTED-MODE ENTRY (GDT + selector
+ far-jump). After CR0.PE=1, the boot does `ljmp 0x08:entry`: the selector (0x08) indexes the GDT
(index = sel >> 3), the descriptor gives the segment BASE, and the CPU resumes 32-bit execution at
base+offset (linear). This models that resolution: selector -> GDT base -> linear far-jump target.
KAT: flat GDT (entry1 base=0, entry2 base=1MB); selector/index extraction; far-jump targets.
HONEST SCOPE: base-direct descriptor model + the resolution; the real 8-byte GDT descriptor packing
(base split / limit / access / granularity) + the EA-opcode decode = refinements. R5 rung-6 = wire
real-mode+seg:off+PE+far-jump into ONE end-to-end "boot to protected mode" run. No hardware writes
(Rule 26). expect_exit: 0 license_tier: ORIGINAL
dependencies 1 imports · 0 importers
imports: nx_syscalls.nx
imported by: nobody (leaf or entry point)
call flow from main pre-order; caps 40 nodes / depth 6 declared; ↻ = already shown
structs
| none |
consts
| none |
functions
| 12 | func fj_puts(s: *u8) -> i64 { var n: i64=0; while s[n]!=(0 as u8){n=n+1} sys_write(1,s,n); return 0 } |
| 13 | func fj_num(v: i64) -> i64 { let b: *u8=sys_mmap(28); var m: i64=v; if m<0{m=0-m;sys_write(1,"-" as *u8,1)} let t: *u8=sys_mmap(28); var k: i64=0; if m==0{t[0]=48 as u8;k=1} while m>0{t[k]=(48+(m%10)) as u8;m=m/10;k=k+1} var i: i64=0; while i<k{b[i]=t[k-1-i];i=i+1} sys_write(1,b,k); return 0 } |
| 16 | func sel_index(sel: i64) -> i64 { return sel >> 3 } called by 1: main |
| 18 | func gdt_base(gdt: *i64, sel: i64) -> i64 { return gdt[sel >> 3] } called by 1: far_target |
| 20 | func far_target(gdt: *i64, sel: i64, off: i64) -> i64 { return gdt_base(gdt, sel) + off } |
| 22 | func main() -> i64 |