segasmp: partially deblob sys_init.o

.gitignore

@@ -1,5 +1,6 @@
 *.o
 !/segasmp/lib/*
+segasmp/lib/sys_init.o
 *.iso
 *.elf
 *.bin

segasmp/lib/sys_init.s

@@ -0,0 +1,110 @@
+	/*
+	This is a partial decompilation of sys_init.o from SBL6.
+
+	This appears to have two independent purposes:
+
+	- *((uint32_t*)(0x0)) = *((uint32_t*)(0x060002dc)) (not sure why that's useful)
+	- copy 88 bytes starting at PATCHPG and ending at ENDOFPG to *(0x06000260)
+
+	Execution continues at the code/section that immediately
+	follows this one. This is by convention whatever is in
+	`smpsys.c`.
+
+	When assembled, this is byte-identical to sys_init.o from
+	SBL6.
+	*/
+
+	.section .text.init
+
+START:
+	mov.l	A_INSTAL,r7 /* 0x06000260 */
+	mov.l	A_SFTRES,r5 /* 0x060002dc */
+	mov.l	@r7,r7
+	mov.l	@r5,r3
+	mova	PATSFTRS,r0 /* 0x00000000 */
+	mov.l	r3,@r0
+
+	/* "INSTALL" is roughly an inlined 'memcpy', which copies PATCHPG to A_INSTAL */
+INSTALL:
+	mova	PATCHPG,r0
+	mov	r7,r1
+	mov	#22,r2 /* PATCHPG is 88 bytes long, and is copied 4 bytes at a time */
+
+INSTAL1:
+	mov.l	@r0+,r4
+	dt	r2
+	mov.l	r4,@r1
+	bf.s	INSTAL1
+	add	#4,r1
+
+SETHOOK:
+	bra	ENDOFPG
+	mov.l	r7,@r5
+
+A_SFTRES:
+	.word 0x0600
+	.word 0x02dc
+
+A_INSTAL:
+	.word 0x0600
+	.word 0x0260
+
+PATCHPG:
+	mov.w	A_CCR,r3 /* 0xfe92 */
+	mov	#0,r0
+	mov.b	r0,@r3
+	mov	#16,r0
+	mov.b	r0,@r3
+	mov.l	@r15+,r0
+	mov.l	A_DEFSTK,r15 /* 0x06002000 */
+	mov.l	r0,@-r15
+	mov.l	PATSFTRS,r1 /* 0x00000000 */
+	mov	#1,r0
+	mov	#3,r4
+	sts.l	pr,@-r15
+	jsr	@r1
+	mov.b	r0,@r3
+
+_CDPAT_InitSctLen:
+	mov.l	CDB_HIRQ,r5 /* 0x25890008 */
+	mov	#-2,r3
+	mov.w	r3,@r5
+	mov.w	CONST_6000,r0 /* 0x6000 */
+	mov.w	r0,@(16,r5)
+	mov	#0,r0
+	mov.w	r0,@(20,r5)
+	mov.w	r0,@(24,r5)
+	mov.w	r0,@(28,r5)
+	mov.w	CONST_0900,r7 /* 0x0900 */
+LOOP:
+	mov.w	@r5,r0
+	tst	#1,r0
+	bf	BREAK_LOOP
+	dt	r7
+	bf	LOOP
+BREAK_LOOP:
+	mov.w	@(16,r5),r0
+	mov.w	@(20,r5),r0
+	lds.l	@r15+,pr
+	mov.w	@(24,r5),r0
+	rts
+	mov.w	@(28,r5),r0
+
+CONST_6000:
+	.word 0x6000
+CONST_0900:
+	.word 0x0900
+A_CCR:
+	.word 0xfe92
+CDB_HIRQ:
+	.word 0x2589
+	.word 0x0008
+
+A_DEFSTK:
+	.word 0x0600
+	.word 0x2000
+
+PATSFTRS:
+	.word 0x0000
+	.word 0x0000
+ENDOFPG: