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Hardware Initialization States
3-22
Table 3–2. State of the Status Register (17 bit) after RESET Low-to-High
(Bits 5 through 16 are left uninitialized)
Bit Bit Name Initialized Value Description
0 XM 0 Extended sign mode disabled
1 UM 0 Unsigned multiplier mode disabled (allows signed multiplier mode)
2 OM 0 Overflow mode disabled (allows ALU normal mode)
3 FM 0
Shift mode for fractional multiplication disabled (allows unsigned
fractional/integer arithmetic)
4 IM 0 Global interrupt enable bit
5 (reserved) Reserved for future use
6 XZF Transfer equal-to-zero status bit
7 XSF Transfer sign status bit
8 RCF Auxiliary register carry-out status bit
9 RZF Auxiliary register equal-to-zero status bit
10 OF
Same state as
Accumulator overflow status bit
11 SF
before RESET
Accumulator sign status bit (extended 17th bit)
12 ZF Accumulator equal-to-zero status bit (16 bits)
13 CF Accumulator carry-out status bit (16th ALU bit)
14 TF1 Test flag 1
15 TF2 Test flag 2
16 TAG Memory tag