From 0a77a11e17f697bf797655c4ae87b927432b1f88 Mon Sep 17 00:00:00 2001
From: user <user@clank>
Date: Thu, 16 Jul 2026 00:04:09 +0200
Subject: kernel: implement exec()

- sys_exec(B=program id): look up ProgramTable, point PROC_ROMB at the program's
  ROM text bank, map it into $4000-$7FFF, reset stack, jp to entry (no return)
- programs.asm: two demo programs (ping/pong) ORG'd at the SAME $4000 in banks
  2 and 3 - proves execution is driven purely by PROC_ROMB
- demo: init forks; parent execs PROG_PING (bank2, '1'), child execs PROG_PONG
  (bank3, '2') -> '1212...', 2000/2000 balanced, zero garbage
- README: document exec + text-in-ROM model
---
 include/gbos.inc | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'include')

diff --git a/include/gbos.inc b/include/gbos.inc
index 0727b02..e15f7cb 100644
--- a/include/gbos.inc
+++ b/include/gbos.inc
@@ -85,4 +85,10 @@ DEF SYS_BRK     EQU 10
 DEF SYS_YIELD   EQU 11
 DEF SYS_MAX     EQU 12
 
+; -----------------------------------------------------------------------------
+; Program table indices (see programs.asm). exec() takes one of these in B.
+; -----------------------------------------------------------------------------
+DEF PROG_PING   EQU 0
+DEF PROG_PONG   EQU 1
+
     ENDC
-- 
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