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Is there a way to change the DEFINE statement to get rid of the two useless mov(s)?
C51 COMPILER V6.02, COMPILATION OF MODULE MAIN OBJECT MODULE PLACED IN .\MAIN.OBJ COMPILER INVOKED BY: C:\PROGRAM FILES\KEIL\C51\BIN\C51.EXE .\MAIN.C OPTIMIZE(7,SPEED) NOINTPROMOTE MODDP2 DEBUG OBJECTEX -TEND CODE SYMBOLS NOCOND stmt level source 1 typedef unsigned char BYTE; 2 typedef unsigned int WORD; 3 4 typedef pdata struct 5 { 6 BYTE PC0 :1; 7 BYTE PC1 :1; 8 BYTE nFifoPend :1; //PC2 9 BYTE PC3 :1; 10 BYTE FpgaReset :1; //PC4 11 BYTE PC5 :1; 12 BYTE PC6 :1; 13 BYTE PC7 :1; 14 } CType; 15 16 extern volatile BYTE pdata xOUTC; 17 18 #define IoPins_FpgaReset ( ((CType pdata*)(&xOUTC))->FpgaReset ) 19 20 void main(void) 21 { 22 1 IoPins_FpgaReset = 1; 23 1 } 24 25 ; FUNCTION main (BEGIN) ; SOURCE LINE # 20 ; SOURCE LINE # 21 ; SOURCE LINE # 22 0000 7A00 E MOV R2,#HIGH xOUTC 0002 7900 E MOV R1,#LOW xOUTC 0004 7800 E MOV R0,#LOW xOUTC 0006 E2 MOVX A,@R0 0007 4410 ORL A,#010H 0009 F2 MOVX @R0,A ; SOURCE LINE # 23 000A 22 RET ; FUNCTION main (END)
1. bit-fields in Keil C (8051's fault) are horribly inefficient. 2. Pdata still requires two bytes for a pointer when we cannot guarantee that the page (a 256 byte block of xdata) is not currently loaded. How does this work for you?
typedef enum { PC0 = 1 << 0, PC1 = 1 << 1, FIFO_PEND = 1 << 2, PC3 = 1 << 3, FPGA_RESET = 1 << 4, PC5 = 1 << 5, PC6 = 1 << 6, PC7 = 1 << 7 } FpgaPortC; typedef unsigned char U8; // I use 'r_' to indicate some sore of register variable. static volatile U8 pdata r_portC _at_ 0x8000; // 0x8000 is a guess. #ifdef MUST_INLINE #define resetFpga() do { r_portC |= FPGA_RESET; } while (0) #else void resetFpga(void) { r_portC |= FPGA_RESET; } #endif void main(void) { resetFpga(); for (;;); } ;; *** No inlining *** ; FUNCTION resetFpga (BEGIN) ; SOURCE LINE # 273 ; SOURCE LINE # 274 ; SOURCE LINE # 275 0000 7800 MOV R0,#LOW r_portC 0002 E2 MOVX A,@R0 0003 4410 ORL A,#010H 0005 F2 MOVX @R0,A ; SOURCE LINE # 276 0006 22 RET ; FUNCTION resetFpga (END) ; FUNCTION main (BEGIN) ; SOURCE LINE # 279 ; SOURCE LINE # 280 ; SOURCE LINE # 281 0000 120000 R LCALL resetFpga ; SOURCE LINE # 283 0003 ?C0002: 0003 80FE SJMP ?C0002 ; FUNCTION main (END) ;; *** Inlining *** ; FUNCTION main (BEGIN) ; SOURCE LINE # 279 ; SOURCE LINE # 280 ; SOURCE LINE # 281 0000 7800 MOV R0,#LOW r_portC 0002 E2 MOVX A,@R0 0003 4410 ORL A,#010H 0005 F2 MOVX @R0,A ; SOURCE LINE # 283 0006 ?C0004: 0006 80FE SJMP ?C0004 ; FUNCTION main (END) In both cases: C51 COMPILER V6.10, COMPILATION OF MODULE UART OBJECT MODULE PLACED IN .\a.OBJ COMPILER INVOKED BY: C:\Keil\C51\BIN\C51.EXE .\a.c BROWSE NOINTPROMOTE DEBUG OBJECTEXTEND CODE PAGEWIDTH(132) PAGELENGTH(6600)
Thanks for the suggestion. However 1. I have never found that the bit-fields in Keil C inefficient. 2. When there is only one page of XDATA (which is common in small designs), it is fairly easy guarantee the correct page is loaded. If fact the 'upper address byte' is irrelevent. In particular, this design is using an Anchor chip that has all of it's control registers on one page. I just load the MPAGE register with the page address once and never have to use the DPTR for control access again.