83Plus:OS:Certificate/Headers:Fields:Application Headers - Revision history

NonstickAtom: Updated some info based off of what the_mad_joob said in Omnimaga.

2020-12-09T18:06:54Z

Updated some info based off of what the_mad_joob said in Omnimaga.

Dr. D'nar: Comment on lack of padding

2014-05-09T22:25:50Z

Comment on lack of padding

Dr. D'nar: fix broken fix

2014-05-09T22:18:55Z

fix broken fix

Dr. D'nar: Put emphasis on app header fields not being fixed-size

2014-05-09T22:13:54Z

Put emphasis on app header fields not being fixed-size

Dr. D'nar: make a note about name lengths

2014-05-07T01:52:50Z

make a note about name lengths

Dr. D'nar: Reference Wiki pages about header fields, which are otherwise a bit hard to find.

2014-02-21T12:05:18Z

Reference Wiki pages about header fields, which are otherwise a bit hard to find.

Geekboy at 04:05, 13 June 2013

2013-06-13T04:05:06Z

Geekboy at 03:12, 13 June 2013

2013-06-13T03:12:37Z

Dr. D'nar: minor fixes

2013-06-10T11:45:44Z

minor fixes

Dr. D'nar: Created page with 'Application Headers Application Headers In the …'

2013-05-29T07:01:17Z

Created page with 'Application Headers Application Headers In the …'

New page

[[Category:83Plus:OS:Certificate/Headers:Fields_By_Number|Application Headers]] [[Category:83Plus:OS:Certificate/Headers:Fields:Application Headers|Application Headers]]

In the past, people liked to treat application headers as structs with fixed positions for everything. This is '''wrong.''' A valid application header must: Start with a master field ([[http://wikiti.brandonw.net/index.php?title=Category:83Plus:OS:Certificate/Headers:Fields:800|800]]), end with a final field ([[83Plus:OS:Certificate/Headers:Fields:807|807]]), contain a name field ([[83Plus:OS:Certificate/Headers:Fields:804|804]]), a key ID field ([[83Plus:OS:Certificate/Headers:Fields:801|801]]), a page count ([[83Plus:OS:Certificate/Headers:Fields:808|808]]), and a date stamp field ([[83Plus:OS:Certificate/Headers:Fields:032|032]]+[[83Plus:OS:Certificate/Headers:Fields:090|090]]) followed by a date stamp signature field ([[83Plus:OS:Certificate/Headers:Fields:020|020]]). Aside from the opening field, closing field, and dates tamp + signature orderings, those fields can be in '''any order.''' You may also specify a build ([[83Plus:OS:Certificate/Headers:Fields:803|803]]) and revision ([[83Plus:OS:Certificate/Headers:Fields:802|802]]) and disable the TI splash screen ([[83Plus:OS:Certificate/Headers:Fields:809|809]]). There's also support for some other stuff, but it is all optional.

In theory, it is legal to specify the master field as 800D xxxx if the application is less than 64 K in size. However, rabbitsign won't sign it.

The name field can be less than 8 bytes, so you do not have to pad app names out to 8 bytes. You can also specify an app name greater than 8 bytes, but the calculator will ignore everything past the 8th byte.

The date stamp signature never actually gets checked, so you can put garbage there. But it gets better! You can also just specify the date stamp signature as having zero length. You can also pull a similar stunt with the date stamp itself.

The final field is usually written as 807F00000000. That four byte length field is ignored, so you can just put 8070 instead.

People like to pad the application header until it is 128 bytes in size. That is not necessary. Execution starts after the app header.

<nowiki> ; Minimal application. This application is just 31 bytes! And takes up 16 K of archive space!
; Master Field
.db 80h, 0Fh, 0, 0, 0, 0
; Name
.db 80h, 43h, "nop"
; Disable TI splash screen. Also, pointer to the jump table.
.db 80h, 90h
; Pages
.db 80h, 81h, 1
; Signing Key ID
.db 80h, 12h, 1, 4 ; or 15 for the TI-84+CSE
; Date stamp. Apparently, the calculator doesn't mind if you put
; nothing in this.
.db 03h, 22h, 09h, 00h
; Date stamp signature. Since nothing ever checks this, there's no
; reason ever to update it. Or even have data in it.
.db 02h, 00
; Final field
.db 80h, 70h
b_call(_JForceCmdNoChar)
</nowiki>

@@ Line 5: / Line 5: @@
 In the past, people liked to treat application headers as structs with fixed positions for everything. This is '''wrong.''' An application header is composed of [[83Plus:OS:Certificate/Headers#Format|variable-length fields]]. A valid application header must: Start with a master field ([[http://wikiti.brandonw.net/index.php?title=Category:83Plus:OS:Certificate/Headers:Fields:800]]), end with a final field ([[83Plus:OS:Certificate/Headers:Fields:807|807]]), contain a name field ([[83Plus:OS:Certificate/Headers:Fields:804|804]]), a key ID field ([[83Plus:OS:Certificate/Headers:Fields:801|801]]), a page count ([[83Plus:OS:Certificate/Headers:Fields:808|808]]), and a date stamp field ([[83Plus:OS:Certificate/Headers:Fields:032|032]]+[[83Plus:OS:Certificate/Headers:Fields:090|090]]) followed by a date stamp signature field ([[83Plus:OS:Certificate/Headers:Fields:020|020]]). Aside from the opening field being first, closing field being last, and dates stamp signature following the date stamp, those fields can be in '''any order.''' You may also specify a build ([[83Plus:OS:Certificate/Headers:Fields:803|803]]) and revision ([[83Plus:OS:Certificate/Headers:Fields:802|802]]) and disable the TI splash screen ([[83Plus:OS:Certificate/Headers:Fields:809|809]]). There's also support for some other stuff, but it is all optional.
-In theory, it is legal to specify the master field as 800D xxxx if the application is less than 64 K in size. However, rabbitsign won't sign it.
+In theory, it is legal to specify the master field as 800DXX or 800EXXXX if the application is less than 64 K in size. However, rabbitsign won't sign it.
 The name field can be less than 8 bytes, so you do not have to pad app names out to 8 bytes. You can also specify an app name greater than 8 bytes, but the calculator will ignore everything past the 8th byte.

@@ Line 3: / Line 3: @@
 ''See also [[83Plus:OS:Certificate/Headers|the page on certificate headers]]; app headers follow the same general format.''
-In the past, people liked to treat application headers as structs with fixed positions for everything. This is '''wrong.''' An application header is composed of [[83Plus:OS:Certificate/Headers#Format|variable-length fields]]. A valid application header must: Start with a master field ([[http://wikiti.brandonw.net/index.php?title=Category:83Plus:OS:Certificate/Headers:Fields:800|800]]), end with a final field ([[83Plus:OS:Certificate/Headers:Fields:807|807]]), contain a name field ([[83Plus:OS:Certificate/Headers:Fields:804|804]]), a key ID field ([[83Plus:OS:Certificate/Headers:Fields:801|801]]), a page count ([[83Plus:OS:Certificate/Headers:Fields:808|808]]), and a date stamp field ([[83Plus:OS:Certificate/Headers:Fields:032|032]]+[[83Plus:OS:Certificate/Headers:Fields:090|090]]) followed by a date stamp signature field ([[83Plus:OS:Certificate/Headers:Fields:020|020]]). Aside from the opening field being first, closing field being last, and dates stamp signature following the date stamp, those fields can be in '''any order.''' You may also specify a build ([[83Plus:OS:Certificate/Headers:Fields:803|803]]) and revision ([[83Plus:OS:Certificate/Headers:Fields:802|802]]) and disable the TI splash screen ([[83Plus:OS:Certificate/Headers:Fields:809|809]]). There's also support for some other stuff, but it is all optional.
+In the past, people liked to treat application headers as structs with fixed positions for everything. This is '''wrong.''' An application header is composed of [[83Plus:OS:Certificate/Headers#Format|variable-length fields]]. A valid application header must: Start with a master field ([[http://wikiti.brandonw.net/index.php?title=Category:83Plus:OS:Certificate/Headers:Fields:800]]), end with a final field ([[83Plus:OS:Certificate/Headers:Fields:807|807]]), contain a name field ([[83Plus:OS:Certificate/Headers:Fields:804|804]]), a key ID field ([[83Plus:OS:Certificate/Headers:Fields:801|801]]), a page count ([[83Plus:OS:Certificate/Headers:Fields:808|808]]), and a date stamp field ([[83Plus:OS:Certificate/Headers:Fields:032|032]]+[[83Plus:OS:Certificate/Headers:Fields:090|090]]) followed by a date stamp signature field ([[83Plus:OS:Certificate/Headers:Fields:020|020]]). Aside from the opening field being first, closing field being last, and dates stamp signature following the date stamp, those fields can be in '''any order.''' You may also specify a build ([[83Plus:OS:Certificate/Headers:Fields:803|803]]) and revision ([[83Plus:OS:Certificate/Headers:Fields:802|802]]) and disable the TI splash screen ([[83Plus:OS:Certificate/Headers:Fields:809|809]]). There's also support for some other stuff, but it is all optional.
 In theory, it is legal to specify the master field as 800D xxxx if the application is less than 64 K in size. However, rabbitsign won't sign it.

@@ Line 3: / Line 3: @@
 ''See also [[83Plus:OS:Certificate/Headers|the page on certificate headers]]; app headers follow the same general format.''
-In the past, people liked to treat application headers as structs with fixed positions for everything. This is '''wrong.''' A valid application header must: Start with a master field ([[http://wikiti.brandonw.net/index.php?title=Category:83Plus:OS:Certificate/Headers:Fields:800|800]]), end with a final field ([[83Plus:OS:Certificate/Headers:Fields:807|807]]), contain a name field ([[83Plus:OS:Certificate/Headers:Fields:804|804]]), a key ID field ([[83Plus:OS:Certificate/Headers:Fields:801|801]]), a page count ([[83Plus:OS:Certificate/Headers:Fields:808|808]]), and a date stamp field ([[83Plus:OS:Certificate/Headers:Fields:032|032]]+[[83Plus:OS:Certificate/Headers:Fields:090|090]]) followed by a date stamp signature field ([[83Plus:OS:Certificate/Headers:Fields:020|020]]). Aside from the opening field being first, closing field being last, and dates stamp signature following the date stamp, those fields can be in '''any order.''' You may also specify a build ([[83Plus:OS:Certificate/Headers:Fields:803|803]]) and revision ([[83Plus:OS:Certificate/Headers:Fields:802|802]]) and disable the TI splash screen ([[83Plus:OS:Certificate/Headers:Fields:809|809]]). There's also support for some other stuff, but it is all optional.
+In the past, people liked to treat application headers as structs with fixed positions for everything. This is '''wrong.''' An application header is composed of [[83Plus:OS:Certificate/Headers#Format|variable-length fields]]. A valid application header must: Start with a master field ([[http://wikiti.brandonw.net/index.php?title=Category:83Plus:OS:Certificate/Headers:Fields:800|800]]), end with a final field ([[83Plus:OS:Certificate/Headers:Fields:807|807]]), contain a name field ([[83Plus:OS:Certificate/Headers:Fields:804|804]]), a key ID field ([[83Plus:OS:Certificate/Headers:Fields:801|801]]), a page count ([[83Plus:OS:Certificate/Headers:Fields:808|808]]), and a date stamp field ([[83Plus:OS:Certificate/Headers:Fields:032|032]]+[[83Plus:OS:Certificate/Headers:Fields:090|090]]) followed by a date stamp signature field ([[83Plus:OS:Certificate/Headers:Fields:020|020]]). Aside from the opening field being first, closing field being last, and dates stamp signature following the date stamp, those fields can be in '''any order.''' You may also specify a build ([[83Plus:OS:Certificate/Headers:Fields:803|803]]) and revision ([[83Plus:OS:Certificate/Headers:Fields:802|802]]) and disable the TI splash screen ([[83Plus:OS:Certificate/Headers:Fields:809|809]]). There's also support for some other stuff, but it is all optional.
 In theory, it is legal to specify the master field as 800D xxxx if the application is less than 64 K in size. However, rabbitsign won't sign it.

← Older revision		Revision as of 12:05, 21 February 2014
Line 1:		Line 1:
	[[Category:83Plus:OS:Certificate/Headers:Fields_By_Number\|Application Headers]] [[Category:83Plus:OS:Certificate/Headers:Fields:Application Headers\|Application Headers]]		[[Category:83Plus:OS:Certificate/Headers:Fields_By_Number\|Application Headers]] [[Category:83Plus:OS:Certificate/Headers:Fields:Application Headers\|Application Headers]]
		+
		+	''See also [[83Plus:OS:Certificate/Headers\|the page on certificate headers]]; app headers follow the same general format.''

	In the past, people liked to treat application headers as structs with fixed positions for everything. This is '''wrong.''' A valid application header must: Start with a master field ([[http://wikiti.brandonw.net/index.php?title=Category:83Plus:OS:Certificate/Headers:Fields:800\|800]]), end with a final field ([[83Plus:OS:Certificate/Headers:Fields:807\|807]]), contain a name field ([[83Plus:OS:Certificate/Headers:Fields:804\|804]]), a key ID field ([[83Plus:OS:Certificate/Headers:Fields:801\|801]]), a page count ([[83Plus:OS:Certificate/Headers:Fields:808\|808]]), and a date stamp field ([[83Plus:OS:Certificate/Headers:Fields:032\|032]]+[[83Plus:OS:Certificate/Headers:Fields:090\|090]]) followed by a date stamp signature field ([[83Plus:OS:Certificate/Headers:Fields:020\|020]]). Aside from the opening field being first, closing field being last, and dates stamp signature following the date stamp, those fields can be in '''any order.''' You may also specify a build ([[83Plus:OS:Certificate/Headers:Fields:803\|803]]) and revision ([[83Plus:OS:Certificate/Headers:Fields:802\|802]]) and disable the TI splash screen ([[83Plus:OS:Certificate/Headers:Fields:809\|809]]). There's also support for some other stuff, but it is all optional.		In the past, people liked to treat application headers as structs with fixed positions for everything. This is '''wrong.''' A valid application header must: Start with a master field ([[http://wikiti.brandonw.net/index.php?title=Category:83Plus:OS:Certificate/Headers:Fields:800\|800]]), end with a final field ([[83Plus:OS:Certificate/Headers:Fields:807\|807]]), contain a name field ([[83Plus:OS:Certificate/Headers:Fields:804\|804]]), a key ID field ([[83Plus:OS:Certificate/Headers:Fields:801\|801]]), a page count ([[83Plus:OS:Certificate/Headers:Fields:808\|808]]), and a date stamp field ([[83Plus:OS:Certificate/Headers:Fields:032\|032]]+[[83Plus:OS:Certificate/Headers:Fields:090\|090]]) followed by a date stamp signature field ([[83Plus:OS:Certificate/Headers:Fields:020\|020]]). Aside from the opening field being first, closing field being last, and dates stamp signature following the date stamp, those fields can be in '''any order.''' You may also specify a build ([[83Plus:OS:Certificate/Headers:Fields:803\|803]]) and revision ([[83Plus:OS:Certificate/Headers:Fields:802\|802]]) and disable the TI splash screen ([[83Plus:OS:Certificate/Headers:Fields:809\|809]]). There's also support for some other stuff, but it is all optional.

@@ Line 34: / Line 34: @@
 	; Final field
 	.db	80h, 70h
 	b_call(_JForceCmdNoChar)
 </nowiki>

@@ Line 18: / Line 18: @@
 	; Master Field
 	.db	80h, 0Fh, 0, 0, 0, 0
-	; Name
+	; Name. Note that the name field reads 80 43 because the name specified here is 3 characters long.
 	.db	80h, 43h, "nop"
 	; Disable TI splash screen.