; testc.SRC generated from: testc.c ; COMPILER INVOKED BY: ; C:KeilC51BINC51.EXE testc.c BROWSE DEBUG OBJECTEXTEND NAME TESTC ?PR?ScanKey?TESTC SEGMENT CODE ?PR?ScanKeySingle?TESTC SEGMENT CODE PUBLIC ScanKeySingle PUBLIC ScanKey ; #pragma SRC ; ; unsigned int ScanKey(void) /* test case to provide */ RSEG ?PR?ScanKey?TESTC ScanKey: USING 0 ; SOURCE LINE # 3 ; { /* compilability */ ; SOURCE LINE # 4 ; return(0x0002); ; SOURCE LINE # 5 MOV R6,#00H MOV R7,#02H ; } ; SOURCE LINE # 6 ?C0001: RET ; END OF ScanKey ; ; unsigned char ScanKeySingle(void) RSEG ?PR?ScanKeySingle?TESTC ScanKeySingle: USING 0 ; SOURCE LINE # 8 ; { ; SOURCE LINE # 9 ; unsigned int key16; ; unsigned char key8 = 16; ; SOURCE LINE # 11 ;---- Variable 'key8?141' assigned to Register 'R5' ---- MOV R5,#010H ; ; /* get the key scan vector */ ; key16 = ScanKey(); ; SOURCE LINE # 14 LCALL ScanKey ;---- Variable 'key16?140' assigned to Register 'R6/R7' ---- ; ; /* exit early if no keys active */ ; if(key16 == 0x0000) ; SOURCE LINE # 17 MOV A,R7 ORL A,R6 JNZ ?C0006 ; { ; SOURCE LINE # 18 ; return(0x80); /* show no key */ ; SOURCE LINE # 19 MOV R7,#080H RET ; } ; SOURCE LINE # 20 ?C0006: ; ; /* scan the 16 bit key vector with 1's for keys pressed */ ; do ; { ; SOURCE LINE # 24 ; if(key16 & 0x8000) /* if a key vector bit is set */ ; SOURCE LINE # 25 MOV A,R6 JNB ACC.7,?C0007 ; { ; SOURCE LINE # 26 ; if(key16 & 0x7FFF) /* if another bit is set */ ; SOURCE LINE # 27 ANL A,#07FH ORL A,R7 JZ ?C0008 ; { ; SOURCE LINE # 28 ; /* show multiple key pressed */ ; return(0x10); ; SOURCE LINE # 30 MOV R7,#010H RET ; } ; SOURCE LINE # 31 ?C0008: ; else ; { ; SOURCE LINE # 33 ; /* singular key found */ ; return(--key8); ; SOURCE LINE # 35 DEC R5 MOV R7,AR5 RET ; } ; SOURCE LINE # 36 ; } ; SOURCE LINE # 37 ?C0007: ; ; key16 <<= 1; /* shift the key bits left */ ; SOURCE LINE # 39 MOV A,R7 ADD A,ACC MOV R7,A MOV A,R6 RLC A MOV R6,A ; ; } while(--key8); ; SOURCE LINE # 41 DJNZ R5,?C0006 ; ; /* default exit for no kwy pressed */ ; return(0x80); /* Note that code never will get here */ ; SOURCE LINE # 44 MOV R7,#080H ; } /* due to the early exit check at beginning */ ; SOURCE LINE # 45 ?C0003: RET ; END OF ScanKeySingle END