darling-libobjc2/objc_msgSend.x86-32.S

102 lines
3.2 KiB
ArmAsm

#define DTABLE_OFFSET 32
#define SMALLOBJ_MASK 1
#define SHIFT_OFFSET 4
#define DATA_OFFSET 12
#define SLOT_OFFSET 16
.macro MSGSEND receiver, sel, fpret
.cfi_startproc
movl \receiver(%esp), %eax
test %eax, %eax # If the receiver is nil
jz 4f # return nil
test $SMALLOBJ_MASK, %eax # Check if the receiver is a small object
jnz 6f # Get the small object class
mov (%eax), %eax # Load the class
1: # classLoaded
movl \sel(%esp), %ecx
mov DTABLE_OFFSET(%eax), %eax # Load the dtable from the class
mov (%ecx), %ecx # Load the selector index
# Register use at this point:
# %eax: dtable
# %ecx: Selector index
# %edx: selector index fragment
mov SHIFT_OFFSET(%eax), %edx # Load the shift (dtable size)
mov DATA_OFFSET(%eax), %eax # load the address of the start of the array
cmpl $8, %edx # If this is a small dtable, jump to the small dtable handlers
je 2f
cmpl $0, %edx
je 3f
mov %ecx, %edx
and $0xff0000, %edx
shrl $14, %edx # Right shift 16, but then left shift by 2 (* sizeof(void*))
add %edx, %eax
mov (%eax), %eax
mov DATA_OFFSET(%eax), %eax
2: # dtable16:
mov %ecx, %edx
and $0xff00, %edx
shrl $6, %edx
add %edx, %eax
mov (%eax), %eax
mov DATA_OFFSET(%eax), %eax
3: # dtable8:
and $0xff, %ecx
shll $2, %ecx
add %ecx, %eax
mov (%eax), %eax
test %eax, %eax
jz 5f # Nil slot - invoke some kind of forwarding mechanism
mov SLOT_OFFSET(%eax), %eax
jmp *%eax
4: # returnNil:
.if \fpret
fldz
.else
xor %eax, %eax # return 0 (int)
xor %edx, %edx # Return 64-bit zero (%edx is
# caller-save, so it's safe to do this in the general case.
.endif
ret
5: # slowSend:
mov \sel(%esp), %ecx
lea \receiver(%esp), %eax
push %ecx # _cmd
push %eax # &self
.cfi_def_cfa_offset 12
call slowMsgLookup@PLT
add $8, %esp # restore the stack
jmp *%eax
6: # smallObject:
push %ebx # Save old %ebx
calll 7f
7:
popl %ebx;
8:
addl $_GLOBAL_OFFSET_TABLE_+(8b-7b), %ebx
leal SmallObjectClasses@GOTOFF(%ebx), %eax
mov (%eax), %eax
popl %ebx
jmp 1b
.cfi_endproc
.endm
.globl CDECL(objc_msgSend_fpret)
TYPE_DIRECTIVE(CDECL(objc_msgSend_fpret), @function)
CDECL(objc_msgSend_fpret):
MSGSEND 4, 8, 1
.globl CDECL(objc_msgSend)
TYPE_DIRECTIVE(CDECL(objc_msgSend), @function)
CDECL(objc_msgSend):
MSGSEND 4, 8, 0
.globl CDECL(objc_msgSend_stret)
TYPE_DIRECTIVE(CDECL(objc_msgSend_stret), @function)
CDECL(objc_msgSend_stret):
MSGSEND 8, 12, 0