From: owner-ammf-digest@smoe.org (alt.music.moxy-fruvous digest) To: ammf-digest@smoe.org Subject: alt.music.moxy-fruvous digest V14 #3741 Reply-To: ammf@fruvous.com Sender: owner-ammf-digest@smoe.org Errors-To: owner-ammf-digest@smoe.org Precedence: bulk alt.music.moxy-fruvous digest Saturday, March 14 2020 Volume 14 : Number 3741 Today's Subjects: ----------------- Skull Knuckle is a hardcore fighting tool ["Punisher Kunckle" Subject: Skull Knuckle is a hardcore fighting tool Skull Knuckle is a hardcore fighting tool http://audigovv.bid/t53RponklskxO6W6HBcw6z1iIO6foSlF4mF_T9rkj98R264 http://audigovv.bid/g56X8q9pPKtrIHhmKvuxhw_pXTBBtGAdrKlGeug4ucqe9KQ A complex conditional branch instruction. The A register was loaded with data retrieved from the address specified by the instruction. (Because the AGC uses ones' complement notation, there are two representations of zero. When all bits are set to zero, this is called plus zero. If all bits are set to one, this is called minus zero.) The diminished absolute value (DABS) of the data was then computed and stored in the A register. If the number was greater than zero, the DABS decrements the value by 1; if the number was negative, it is complemented before the decrement is appliedbthis is the absolute value. Diminished means "decremented but not below zero". Therefore, when the AGC performs the DABS function, positive numbers will head toward plus zero, and so will negative numbers but first revealing their negativity via the four-way skip below. The final step in CCS is a four-way skip, depending upon the data in register A before the DABS. If register A was greater than 0, CCS skips to the first instruction immediately after CCS. If register A contained plus zero, CCS skips to the second instruction after CCS. Less than zero causes a skip to the third instruction after CCS, and minus zero skips to the fourth instruction after CCS. The primary purpose of the count was to allow an ordinary loop, controlled by a positive counter, to end in a CCS and a TC to the beginning of the loop, equivalent to an IBM 360's BCT. The absolute value function was deemed important enough to be built into this instruction; when used for only this purpose, the sequence after the CCS was TC *+2, TC *+2, AD ONE. A curious side effect was the creation and use of CCS-holes when the value being tested was known to be never positive, which occurred more often than one might suppose. That left two whole words unoccupied, and a special committee was responsible for assigning data constants to these holes. INDEX Add the data retrieved at the address specified by the instruction to the next instruction. INDEX can be used to add or subtract an index value to the base address specified by the operand of the instruction that follows INDEX. This method is used to implement arrays and table look-ups; since the addition was done on both whole words, it was also used to modify the op. code in a following (extracode) instruction, and on rare occasions both functions at onc ------------------------------ End of alt.music.moxy-fruvous digest V14 #3741 **********************************************