volatile int tbuf[20], result;
    while (1)
    {
        int t = 0;
        for (unsigned char c = 0; c < sizeof(tbuf)/sizeof(int); c++)
        {
            t += tbuf[c];
        }
        
        t /= sizeof(tbuf)/sizeof(int);            //деление INT на SIZE_T, приводящее к "тихой" ошибке
        
        result = t < 0 ? t/5 : t;

    }

6a: 60 e0 ldi r22, 0x00 ; 0
6c: 70 e0 ldi r23, 0x00 ; 0
6e: 80 e0 ldi r24, 0x00 ; 0
70: 90 e0 ldi r25, 0x00 ; 0
72: fb 01 movw r30, r22
74: ee 0f add r30, r30
76: ff 1f adc r31, r31
78: 21 e0 ldi r18, 0x01 ; 1
7a: 30 e0 ldi r19, 0x00 ; 0
7c: 2c 0f add r18, r28
7e: 3d 1f adc r19, r29
80: e2 0f add r30, r18
82: f3 1f adc r31, r19
84: 20 81 ld r18, Z
86: 31 81 ldd r19, Z+1 ; 0x01
88: 82 0f add r24, r18
8a: 93 1f adc r25, r19
8c: 6f 5f subi r22, 0xFF ; 255
8e: 7f 4f sbci r23, 0xFF ; 255
90: 64 31 cpi r22, 0x14 ; 20
92: 71 05 cpc r23, r1
94: 71 f7 brne .-36 ; 0x72 <main+0x1c>
96: 03 d0 rcall .+6 ; 0x9e <__udivmodhi4>
98: 7a a7 std Y+42, r23 ; 0x2a
9a: 69 a7 std Y+41, r22 ; 0x29
9c: e6 cf rjmp .-52 ; 0x6a <main+0x14>

\ ??main_1:
\ 00000004 E045 LDI R20, 5
\ 00000006 E050 LDI R21, 0
\ 00000008 .... RCALL ?SS_DIVMOD_L02
\ ??main_2:
\ 0000000A 8308 ST Y, R16
\ 0000000C 8319 STD Y+1, R17
\ ??main_0:
\ 0000000E E000 LDI R16, 0
\ 00000010 E010 LDI R17, 0
\ 00000012 E020 LDI R18, 0
\ ??main_3:
\ 00000014 2FEC MOV R30, R28
\ 00000016 5FEE SUBI R30, 254
\ 00000018 2F32 MOV R19, R18
\ 0000001A 0F33 LSL R19
\ 0000001C 0FE3 ADD R30, R19
\ 0000001E 8140 LD R20, Z
\ 00000020 8151 LDD R21, Z+1
\ 00000022 0F04 ADD R16, R20
\ 00000024 1F15 ADC R17, R21
\ 00000026 9523 INC R18
\ 00000028 3124 CPI R18, 20
\ 0000002A F3A0 BRCS ??main_3
\ 0000002C E144 LDI R20, 20
\ 0000002E E050 LDI R21, 0
\ 00000030 .... RCALL ?SS_DIVMOD_L02
\ 00000032 2311 TST R17
\ 00000034 F33A BRMI ??main_1
\ 00000036 CFE9 RJMP ??main_2

00000c  2314              MOVS     r3,#0x14
00000e  466a              MOV      r2,sp                ;33
;;;37             
;;;38             result = t < 0 ? t/5 : t;
000010  2405              MOVS     r4,#5
                  |L1.18|
000012  2100              MOVS     r1,#0                ;30
000014  ea4f0001          MOV.W    r0,r1                ;31
                  |L1.24|
000018  f8525020          LDR      r5,[r2,r0,LSL #2]    ;33
00001c  1c40              ADDS     r0,r0,#1             ;31
00001e  4429              ADD      r1,r1,r5             ;33
000020  2814              CMP      r0,#0x14             ;31
000022  d3f9              BCC      |L1.24|
000024  fbb1f0f3          UDIV     r0,r1,r3             ;36
000028  2800              CMP      r0,#0
00002a  da01              BGE      |L1.48|
00002c  fb90f0f4          SDIV     r0,r0,r4
                  |L1.48|
;;;39    
;;;40         }
000030  9014              STR      r0,[sp,#0x50]
000032  e7ee              B        |L1.18|