40
edits
Changes
Added description for syscalls using ARM syscall instruction.
Line 1:
Line 1:
+
There are 2 types of syscalls:
+
+1. Syscalls using undefined ARM instruction.
+
+2. Syscalls using ARM syscall instruction.
+
+== Syscalls (via undefined instructions) ==
Internally, IOS uses a syscall table that is stored toward the end of the binary. The exact address varies with version of IOS, but there are two methods to locate it:
Internally, IOS uses a syscall table that is stored toward the end of the binary. The exact address varies with version of IOS, but there are two methods to locate it:
Line 327:
Line 334:
|}
|}
[[Category:Wii_Hardware]]
[[Category:Wii_Hardware]]
+
+== Syscalls (via ARM syscall instruction) ==
+These types of syscalls are created with the ARM syscall instruction. The exception handler is empty and just do nothing and returns. It seems that these syscalls are only for debugging when Nintendo changes something at the IOS. The syscall is called as follows:
+
+<source lang="c">
+MOVS r0, #syscall_number
+SVC 0xAB
+</source>
+
+Register r0 takes the syscall number.
+Register r1 takes the first parameter.
+
+{|border=1
+|-
+! ID # !! Internal name !! Description !! Return value
+|-
+| 4 || puts(const char *string) || Prints debug message. || unknown.
+|}