Hi,
you can boil down the code that was cited in the original code from 101 bytes to 45 bytes with:

#include <8052.h>

static unsigned char ms_tenth;
static unsigned char servo1_target;
static unsigned char servo2_target;
static unsigned char servo3_target;

void Timer0_ISR (void) interrupt 1 {

    P1_2 = (ms_tenth < servo1_target);
    P1_3 = (ms_tenth < servo2_target);
    P1_4 = (ms_tenth < servo3_target);

    if (++ms_tenth == 180)
        ms_tenth = 0;

    TF0 = 0;
}

void main(void){}
 

As a bonus the code looks more readable (at least to me:) This is the generated assembler code:

   0000                     374 _Timer0_ISR:
   0000 C0 E0               383         push    acc
   0002 C0 D0               384         push    psw
   0004 75 D0 00            385         mov     psw,#0x00
                            386 ;       servo_bitops.c:12: P1_2 = (ms_tenth < servo1_target);
   0007 C3                  387         clr     c
   0008 E5*00               388         mov     a,_ms_tenth
   000A 95*01               389         subb    a,_servo1_target
   000C 92 92               390         mov     _P1_2,c
                            391 ;       servo_bitops.c:13: P1_3 = (ms_tenth < servo2_target);
   000E C3                  392         clr     c
   000F E5*00               393         mov     a,_ms_tenth
   0011 95*02               394         subb    a,_servo2_target
   0013 92 93               395         mov     _P1_3,c
                            396 ;       servo_bitops.c:14: P1_4 = (ms_tenth < servo3_target);
   0015 C3                  397         clr     c
   0016 E5*00               398         mov     a,_ms_tenth
   0018 95*03               399         subb    a,_servo3_target
   001A 92 94               400         mov     _P1_4,c
                            401 ;       servo_bitops.c:16: if (++ms_tenth == 180)
   001C 05*00               402         inc     _ms_tenth
   001E 74 B4               403         mov     a,#0xB4
   0020 B5*00 03            404         cjne    a,_ms_tenth,00102$
                            405 ;       servo_bitops.c:17: ms_tenth = 0;
   0023 75*00 00            406         mov     _ms_tenth,#0x00
   0026                     407 00102$:
                            408 ;       servo_bitops.c:19: TF0 = 0;
   0026 C2 8D               409         clr     _TF0
   0028 D0 D0               410         pop     psw
   002A D0 E0               411         pop     acc
   002C 32                  412         reti

 

Might be enough to allow adding another one or two servos...