From b72dc79eec3d369a38202522165f5ef4cfa5b98b Mon Sep 17 00:00:00 2001 From: Jose Antonio Ortega Ruiz Date: Tue, 9 Apr 2019 02:40:05 +0100 Subject: Support IOC commands for disk/drum devices Thanks to Kevin Brunelle There is a minor fix included with regards to tape devices. The test was failing if M == 0, when it should fail when M != 0. NOTICE: This patch changes the behavior of the VM and changes the function parameters for the ioc_ function. Documentation changes are included. Permits the following: LDX BLKNUM IOC 0(8) OUT ADDR(8) Write block from ADDR into disk[BLKNUM] IOC 0(8) IN ADDR(8) Read block from disk[BLKNUM] into ADDR ... BLKNUM CON 45000 Example possible block on disk I was having an issue writing a block to a drive and then reading back the same block. Because it is impossible to move the SEEK_CUR pointer backwards on a disk device, there was no way for a program to read back a block that it wrote to a disk without restarting or fiddling with ~/.mdk/disk?.dev files and symbolic links. I have added a function parameter to the ioc_ function and used it to pass the value of rX to ioc_. This permits us to use IOC commands to move the read/write head on a disk/drum device. I believe that this conforms to the potential meaning of Knuth's description of IOC for disk/drum devices. I have put in tests to verify that rX is positive and M = 0. I have updated the documentation to reflect this new behavior. This makes disks much more usable. Note: I won't be offended if this patch is rejected because it changed the behavior of the VM. I think it fits the spirit and enhances the functionality in a way that some might find useful. I wanted it for something I was working on, and I felt others might want the same. The thing with the paper-tape should be fixed, though. --- mixlib/xmix_device.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mixlib/xmix_device.h') diff --git a/mixlib/xmix_device.h b/mixlib/xmix_device.h index 13950c9..4de321d 100644 --- a/mixlib/xmix_device.h +++ b/mixlib/xmix_device.h @@ -32,7 +32,7 @@ extern gchar *DEV_DIR_; /* table of overridable device operations */ typedef gboolean (*mix_dev_write_func_t) (mix_device_t *, const mix_word_t *); typedef gboolean (*mix_dev_read_func_t) (mix_device_t *, mix_word_t *); -typedef gboolean (*mix_dev_ioc_func_t) (mix_device_t *, mix_short_t); +typedef gboolean (*mix_dev_ioc_func_t) (mix_device_t *, mix_short_t, mix_word_t); typedef gboolean (*mix_dev_busy_func_t) (const mix_device_t *); typedef void (*mix_dev_destroy_t) (mix_device_t *); -- cgit v1.2.3