✎ soc:2008:dverkamp:journal:start

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====== Daniel Verkamp: COMBOOT Support ======

===== Journal =====

==== Week 0 ====

=== 19 May 2008 ===

Journal created. 

=== 21 May 2008 ===

  * Image type detection by filename: check image->uri?
  * arch/i386/README.i386: use libpm for COM32 transitions, librm for 16-bit COMBOOT
  * hook_bios_interrupt -> hook the COMBOOT API ints (for 16-bit) with stubs that call back into gPXE?
  * REAL_CODE, PHYS_CODE in inline asm
  * memcpy_user, real_to_user
  * i386_all_regs, regs_t (ordered like PUSHA) types
  * _virt_to_phys to switch from etherboot-style virtual address space to flat physical addresses (COM32)
  * basemem_packet (BASEMEM_PACKET_LEN = 1514)
  * arch/i386/include/virtaddr.h: VIRTUAL/PHYSICAL/REAL_CS/DS
  * install_rm_callback_interface
  * Split COMBOOT and C32 or use the same image type for both?

== TODO ==

  * Check current PXE API support
  * Find out how to add config option for image type

=== 23 May 2008 ===

  * Had meeting with mdc and mcb30; discussed basic architecture for COMBOOT support
  * Discovered how near RET from 16-bit COMBOOT works - INT 20h at byte 0 of segment (documented as part of PSP in COMBOOT spec)
  * Sample hook_bios_interrupt/call_prot code from mcb30; see [[soc/2008/dverkamp/notes/hook_bios_interrupt]]
  * Finished basic 16-bit COMBOOT loading and INT 20h and INT 21h AH=02h hooks {{:soc:2008:dverkamp:journal:dverkamp-may-23-2008.png|}}

=== 24 May 2008 ===

  * Figured out and fixed why RET wasn't working - top of stack wasn't being cleared
  * Cleaned up and committed beginnings of COMBOOT API

==== Week 1 ====

=== 25-26 May 2008 ===

  * Allow COMBOOT images to return via INT 20h - save the (far) return address during exec, then save the old stack address in the PSP, so in INT 20h handler, just change back to old stack and do RETF
  * Handle other termination API functions (INT 21h, AH=00h and AH=4Ch) - call INT 20h handler
  * Handle INT 21h, AH=09h (Write DOS String to Console) and AH=30h (Check DOS Version)

=== 29 May 2008 ===

  * Add beginning of SYSLINUX AX=0001h (get version) and AX=0003h (run command)
  * Run command function was looping on itself (comboot executable ran again when "boot" executed?), so did similar "unregister image while running" like image/script.c

Trace: • the_kernel_2 • stefanha • week1 • san_transfer • asdlkf • week7 • week1 • project_plan • project_plan • less1 • under_construction • week4 • staging • week4 • project_plan