FreeCalypso > hg > freecalypso-reveng

changeset 6:8c2621b2ed37

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boot ROM re: further understanding of the external flash image booting
author Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
date Tue, 16 Apr 2013 06:59:35 +0000
parents 9db4dcf94128
children a445735685ba
files bootrom.disasm
diffstat 1 files changed, 14 insertions(+), 9 deletions(-) [+]
line wrap: on
line diff
--- a/bootrom.disasm	Tue Apr 16 06:23:14 2013 +0000
+++ b/bootrom.disasm	Tue Apr 16 06:59:35 2013 +0000
@@ -9,7 +9,7 @@
       1c:	ea200004 	b	0x800034
 
       20:	e24dd004 	sub	sp, sp, #4	; 0x4
-      24:	e59f20b8 	ldr	r2, [pc, #184]	; 0xe4
+      24:	e59f20b8 	ldr	r2, =0xFFFFFB10	; via 0xe4
       28:	e1d2c0b0 	ldrh	r12, [r2]
       2c:	e20c10ff 	and	r1, r12, #255	; 0xff
       30:	e20ccb3f 	and	r12, r12, #64512	; 0xfc00
@@ -29,7 +29,7 @@
       68:	e1a0c82c 	mov	r12, r12, lsr #16
       6c:	e1c2c0b0 	strh	r12, [r2]
       70:	e3a0cfc3 	mov	r12, #780	; 0x30c
-      74:	e59f006c 	ldr	r0, [pc, #108]	; 0xe8
+      74:	e59f006c 	ldr	r0, =0x80F5	; via 0xe8
       78:	e10200bc 	strh	r0, [r2, -r12]
       7c:	e3a0c000 	mov	r12, #0	; 0x0
       80:	e1cdc0b0 	strh	r12, [sp]
@@ -58,8 +58,9 @@
       dc:	e28dd004 	add	sp, sp, #4	; 0x4
       e0:	e12fff1e 	bx	lr
 
-      e4:	fffffb10 	swinv	0x00fffb10
-      e8:	000080f5 	streqd	r8, [r0], -r5
+; literal pool
+      e4:	fffffb10
+      e8:	000080f5
 
       ec:	e92d4010 	stmdb	sp!, {r4, lr}
       f0:	e59fcd0c 	ldr	r12, [pc, #3340]	; 0xe04
@@ -1240,12 +1241,13 @@
     122c:	e3a00000 	mov	r0, #0	; 0x0
     1230:	ebffff96 	bl	0x1090
 ; A valid image is present.
+; set bit 6 in FFFF:FD02 again
     1234:	e1d6c0b0 	ldrh	r12, [r6]
     1238:	e38cc040 	orr	r12, r12, #64	; 0x40
     123c:	e1c6c0b0 	strh	r12, [r6]
-    1240:	e59f10b0 	ldr	r1, [pc, #176]	; 0x12f8
+    1240:	e59f10b0 	ldr	r1, =0x800524	; via 0x12f8
     1244:	e2415004 	sub	r5, r1, #4	; 0x4
-    1248:	e59f40b0 	ldr	r4, [pc, #176]	; 0x1300
+    1248:	e59f40b0 	ldr	r4, =0x373C	; via 0x1300
     124c:	e1a00005 	mov	r0, r5
     1250:	ebffff57 	bl	0xfb4
     1254:	e3500000 	cmp	r0, #0	; 0x0
@@ -1254,11 +1256,13 @@
     1260:	1afffff9 	bne	0x124c
     1264:	e3500001 	cmp	r0, #1	; 0x1
     1268:	0a00000c 	beq	0x12a0
+; clear bit 6 in FFFF:FD02
     126c:	e1d6c0b0 	ldrh	r12, [r6]
     1270:	e20c00bf 	and	r0, r12, #191	; 0xbf
     1274:	e20cccff 	and	r12, r12, #65280	; 0xff00
     1278:	e180c00c 	orr	r12, r0, r12
     127c:	e1c6c0b0 	strh	r12, [r6]
+; transfer control to the flash image?
     1280:	e3a0ca02 	mov	r12, #8192	; 0x2000
     1284:	e59c0000 	ldr	r0, [r12]
     1288:	e1b010a0 	movs	r1, r0, lsr #1
@@ -1267,7 +1271,8 @@
     1294:	eb0000bc 	bl	0x158c
     1298:	eafffffe 	b	0x1298
     129c:	eafffffe 	b	0x129c
-    12a0:	e59fc050 	ldr	r12, [pc, #80]	; 0x12f8
+; interactive mode entry?
+    12a0:	e59fc050 	ldr	r12, =0x800524	; via 0x12f8
     12a4:	e5dc0000 	ldrb	r0, [r12]
     12a8:	e3a01001 	mov	r1, #1	; 0x1
     12ac:	e3a02002 	mov	r2, #2	; 0x2
@@ -1522,7 +1527,7 @@
     1598:	0a000001 	beq	0x15a4
     159c:	e3a00001 	mov	r0, #1	; 0x1
     15a0:	e8bd8010 	ldmia	sp!, {r4, pc}
-    15a4:	e59f0054 	ldr	r0, [pc, #84]	; 0x1600
+    15a4:	e59f0054 	ldr	r0, =0xFFFFFB10	; via 0x1600
     15a8:	e1d0c0b0 	ldrh	r12, [r0]
     15ac:	e20c20ff 	and	r2, r12, #255	; 0xff
     15b0:	e20ccb3f 	and	r12, r12, #64512	; 0xfc00
@@ -1540,7 +1545,7 @@
     15e0:	18bd8010 	ldmneia	sp!, {r4, pc}
     15e4:	e3a00020 	mov	r0, #32	; 0x20
     15e8:	e3a010cc 	mov	r1, #204	; 0xcc
-    15ec:	e59f2010 	ldr	r2, [pc, #16]	; 0x1604
+    15ec:	e59f2010 	ldr	r2, =0x800038	; via 0x1604
     15f0:	eb000019 	bl	0x165c
     15f4:	e1a00004 	mov	r0, r4
     15f8:	eb1ffa8e 	bl	0x800038