PMAC/PMAC2 V1.17C A DDENDUM J UL -2005 New/Revised Saved Setup Registers Y:$0720 – Y:$073F Conversion Table Setup Lines … Parallel Feedback Entries ($2, $3, $6, $7) [Modified]: The “parallel feedback” entries read a word from the address specified in the low 16 bits (bits 0 – 15) of the first line, either a whole word from the single address specified, or three bytes from three consecutive Y-word addresses starting at the specified address. The four methods in this class, specified by the first hex digit (bits 20 – 23) are: • $2: Y-word parallel, no filtering (2-line entry) • $3: Y-word parallel, with filtering (3-line entry) • $6: X-word parallel, no filtering (2-line entry) • $7:
X-word parallel, with filtering (3-line entry) The second hex digit (bits 16 – 19) contains four mode-control bits that govern how the conversion is done. The four mode-control bits are: • Bit 16 (digit value 1): Summing control (0 = no summing; 1 = sum with above result) for word-wide reads only; byte-select bit 0 for byte-wide reads only (depending on bit 18) • Bit 17 (digit value 2): Reserved for word-wide reads, byte-select bit 1 for byte-wide reads • Bit 18 (digit value 4): Shift-right/byte-wide-read control (depending on bits 16 and 17) • Bit 19 (digit value 8):
Shift-left control (0 = normal 5-bit left shift; 1 = no or right shift) These four bits provide multiple combinations for the second hex digit, shown in the following table:
V1.17C Firmware Version 15 Second Digit Conversion Details Second Digit Conversion Details $0 Word-wide source, shift result left 5 bits, no summing $8 Word-wide source, no shift of result, no summing $1 Word-wide source, shift result left 5 bits, summed with above result $9 Word-wide source, no shift of result, summed with above result $2 (Reserved) $A (Reserved) $3 (Reserved) $B (Reserved) $4 (Reserved) $C Word-wide source, shift result right 3 bits, no summing $5 Byte-wide Y source (low byte), shift result left 5 bits, no summing $D Byte-wide Y source (low byte), no shift of result, no summing $6 Byte-wide Y source (middle byte), shift result left 5 bits, no summing $E Byte-wide Y source (middle byte), no shift of result, no summing $7 Byte-wide Y source (high byte), shift result left 5 bits, no summing $F Byte-wide Y source (high byte), no shift of result, no summing