Is this a BUG??

121: void Uart_Receive_Data(void) ----> interrupt route(USING 1) called fun

122: {

123: Tinbuf[Tiend++ & (ILEN-1)] = UartBuf_R;

124:
C:0x0212 7818 MOV R0,#UartBuf_R(0x18)
C:0x0214 E6 MOV A,@R0
C:0x0215 FF MOV R7,A--------------------------> UartBuf_R

C:0x0216 781A MOV R0,#Tiend(0x1A)
C:0x0218 E6 MOV A,@R0
C:0x0219 06 INC @R0
C:0x021A 5407 ANL A,#Sys_100us_FLG(0x07)
C:0x021C 2410 ADD A,#ReceiveWait(0x10)
C:0x021E F8 MOV R0,A
C:0x021F A607 MOV @R0,Sys_100us_FLG(0x07)------->Tinbuf[Tiend++ & (ILEN-1)]

------------------------------------------------------------>R7 equ 0x07??

125: P2=Tinbuf[(Tiend-1) & (ILEN-1)];
C:0x0221 781A MOV R0,#Tiend(0x1A)
C:0x0223 E6 MOV A,@R0
C:0x0224 14 DEC A
C:0x0225 5407 ANL A,#Sys_100us_FLG(0x07)
C:0x0227 2410 ADD A,#ReceiveWait(0x10)
C:0x0229 F8 MOV R0,A
C:0x022A E6 MOV A,@R0
C:0x022B F5A0 MOV PPAGE_SFR(0xA0),A 163: }