Now we create our second IPL card containing additional CCWs for reading the cards containing the executable program.\u00a0 The first CCW contained on this card is branched to by the channel because of the TIC (Transfer In Command) CCW in the previous card.<\/p>\n
CARD1 DS 0D\r\n*\r\nCCW3\u00a0\u00a0 DC\u00a0\u00a0 \u00a0X\u201902\u2019\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 * Read\r\n DC\u00a0\u00a0 \u00a0AL3(1024)\u00a0\u00a0 * Storage Address For Data\r\n DC\u00a0\u00a0 \u00a0X\u201960\u2019\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0 * SLI + CC\r\n DC\u00a0\u00a0 \u00a0X\u201900\u2019\r\n DC\u00a0\u00a0 \u00a0AL2(80)\u00a0 \u00a0\u00a0\u00a0 * Length\r\n*\r\n*\r\nCCW4\u00a0\u00a0 DC\u00a0\u00a0 \u00a0X\u201902\u2019\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 * Read\r\n DC\u00a0\u00a0 \u00a0AL3(1024+80) * Storage Address For Data\r\n DC\u00a0\u00a0 \u00a0X\u201960\u2019\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 * SLI + CC\r\n DC\u00a0\u00a0 \u00a0X\u201900\u2019\r\n DC\u00a0\u00a0 \u00a0AL2(80)\u00a0\u00a0\u00a0\u00a0 * Length\r\n*\r\n*\r\nCCW5\u00a0\u00a0 DC\u00a0\u00a0 \u00a0X\u201902\u2019\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 * Read\r\n DC\u00a0\u00a0 \u00a0AL3(1024+160) * Storage Address For Data\r\n DC\u00a0\u00a0 \u00a0X\u201920\u2019\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 * SLI\r\n \u00a0DC\u00a0\u00a0 \u00a0X\u201900\u2019\r\n DC\u00a0\u00a0 \u00a0AL2(80)\u00a0\u00a0\u00a0\u00a0 * Length\r\n*\r\n*<\/pre>\nThere are three CCWs used to read the next three cards.\u00a0 The first card will be read into location 1024.\u00a0 The second card will be read into location 1104 (1024+80) and the third to location 1184 (1024+160).\u00a0 The final CCW does not have the Command Chain bit set.\u00a0 This will cause the channel program to end after this read is completed.<\/p>\n
When the CCWs on this card have executed we will have read 240 bytes of data into memory beginning at location 1024.\u00a0 This is the same address we specified as the beginning execution address in our load PSW on the first card.<\/p>\n
When the final IPL CCW has completed successfully, the CPU will complete the IPL process by loading the initial PSW and begin execution at the address specified.\u00a0 This will cause our small program to begin executing.<\/p>\n
[Next – 80-80 List Executable Code]<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
Now we create our second IPL card containing additional CCWs for reading the cards containing the executable program.\u00a0 The first CCW contained on this card is branched to by the channel because of the TIC (Transfer In Command) CCW in … Continue reading