I am facing strange issue with STM32 IDE (Code Generated by Assembly code)
C Code:
case SET_TIMER: Gst_FlashMemoryData.u8_SetTimerMode = (uint8_t)u16_Display2Info - (uint8_t)START_TIMER_MODE_OFFSET; // START_TIMER_MODE_OFFSET is equal to 8
break;
Assembly Code Generated by the Compiler:
281 case SET_TIMER: Gst_FlashMemoryData.u8_SetTimerMode = (uint8_t)u16_Display2Info - (uint8_t)START_TIMER_MODE_OFFSET;
08000c58: ldr r3, [pc, #40] ; (0x8000c84 <EnterKeyHandler+168>)
08000c5a: ldr r2, [pc, #44] ; (0x8000c88 <EnterKeyHandler+172>)
08000c5c: ldrh r3, [r3, #0]
08000c5e: adds r3, #2
08000c60: strb r3, [r2, #12]
282 break;
08000c62: b.n 0x8000c00 <EnterKeyHandler+36>
Register Values:
General Registers General Purpose and FPU Register Group
r0 8
r1 16
r2 0x2000007c (Hex)
r3 9
r4 536871118
r5 0
r6 -1
r7 -1
r8 -1
r9 536871388
r10 -1
r11 -1
r12 0
sp 0x20001f70
lr 134221013
pc 0x8000c5e <EnterKeyHandler+130>
xpsr 16777234
PRIMASK 0
BASEPRI 0
FAULTMASK 0
CONTROL 0
MSP 536878960
PSP -4
What I observed is
08000c5c: ldrh r3, [r3, #0] // It reads the value from Global Variable -> r3 (9)
08000c5e: adds r3, #2 // Instead of subtracting by 8, it adds and stores it back.
08000c60: strb r3, [r2, #12]
I am unable to understand what really went wrong in my code. Any clue in this regard would be appreciated.
