来源:PM0214 Rev 10,Page 21 ## Application program status register The APSR contains the current state of the condition flags from previous instruction executions. See the register summary in Table 3 on page 18 for its attributes. The bit assignment is: **Table 5. APSR bit definitions** | Bits | Description | |------|-------------| | Bit 31 | N: Negative or less than flag: 0: Operation result was positive, zero, greater than, or equal; 1: Operation result was negative or less than. | | Bit 30 | Z: Zero flag: 0: Operation result was not zero; 1: Operation result was zero. | | Bit 29 | C: Carry or borrow flag: 0: Add operation did not result in a carry bit or subtract operation resulted in a borrow bit; 1: Add operation resulted in a carry bit or subtract operation did not result in a borrow bit. | | Bit 28 | V: Overflow flag: 0: Operation did not result in an overflow; 1: Operation resulted in an overflow. | | Bit 27 | Q: DSP overflow and saturation flag: Sticky saturation flag. 0: Indicates that saturation has not occurred since reset or since the bit was last cleared to zero; 1: Indicates when an SSAT or USAT instruction results in saturation, or indicates a DSP overflow. This bit is cleared to zero by software using an MRS instruction. | | Bits 26:20 | Reserved. | | Bits 19:16 | GE[3:0]: Greater than or Equal flags. See SEL on page 105 for more information. | | Bits 15:0 | Reserved. | > 原始图片:imgs/page_21_cover.png(无图则注明无图)