SDCC has data types for 16 and 32 bit SFR so translating your assembly code to C is straightforward:

#include <8052.h>

/* It is highly encouraged to have a look into
   the include file compiler.h
   http://svn.sourceforge.net/viewvc/sd...iew=markup
   if you want to share header files between different compilers: */
#include <compiler.h>


/* you did not tell the addresses so
   you have to adapt these to your hardware */
SFR    (APBBR_OPCODE, 0xE6);
SFR16  (APBBR_ADDR,   0xE0);
//SFR16E (APBBR_ADDR,   0xE1E0);
SFR32  (APBBR_RDATA,  0xE2);
//SFR32E (APBBR_RDATA,  0xE5E4E3E2);

#define APBBR_OP_SINGLE_READ (0x0a)


unsigned long APBBR_read_data(unsigned int addr)
{
  bit tmp_EA = EA;

  EA = 0;
  APBBR_ADDR = addr;
  APBBR_OPCODE = APBBR_OP_SINGLE_READ;

  __asm nop __endasm;

  EA = tmp_EA;
  return APBBR_RDATA;
}

compiles to:

   0000                     340 _APBBR_read_data:
   0000 AA 82               350 	mov	r2,dpl
   0002 AB 83               351 	mov	r3,dph
                            352 ;	sfr32.c:21: bit tmp_EA = EA;
   0004 A2 AF               354 	mov	c,_EA
   0006 92*00               355 	mov	_APBBR_read_data_tmp_EA_1_1,c
                            356 ;	sfr32.c:23: EA = 0;
   0008 C2 AF               358 	clr	_EA
                            359 ;	sfr32.c:24: APBBR_ADDR = addr;
   000A 8A E0               361 	mov	_APBBR_ADDR,r2
   000C 8B E1               362 	mov	(_APBBR_ADDR >> 8),r3
                            363 ;	sfr32.c:25: APBBR_OPCODE = APBBR_OP_SINGLE_READ;
   000E 75 E6 0A            365 	mov	_APBBR_OPCODE,#0x0A
                            366 ;	sfr32.c:27: __asm	nop __endasm;
   0011 00                  368 	 nop 
                            369 ;	sfr32.c:29: EA = tmp_EA;
   0012 A2*00               371 	mov	c,_APBBR_read_data_tmp_EA_1_1
   0014 92 AF               372 	mov	_EA,c
                            373 ;	sfr32.c:30: return APBBR_RDATA;
   0016 85 E2 82            375 	mov	dpl,_APBBR_RDATA
   0019 85 E3 83            376 	mov	dph,(_APBBR_RDATA >> 8)
   001C 85 E4 F0            377 	mov	b,(_APBBR_RDATA >> 16)
   001F E5 E5               378 	mov	a,(_APBBR_RDATA >> 24)
   0021 22                  380 	ret

(No library calls involved)

If your code is really time critical please see manual section 3.12 Inline Assembler Code

Happy hacking!