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3b2: STRCPY fix, CTC and NI cleanup

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- The previous fix for STRCPY introduced a new bug. STRCPY must always
  copy the final NULL terminator of the string, but must NOT increment
  the source or destination pointers for the NULL terminator.

- The CTC simulation did not correctly support streaming mode, which
  can in some cases request reads that are not on 512-byte block
  boundaries.

- To begin to support System V Release 4 UNIX, the NI card (called EMD
  under SVR4) needed to support several more CRC codes for pump code.
This commit is contained in:
Seth Morabito
2019-08-15 07:58:16 -07:00
parent 61e101b5e2
commit 9736cc3116
7 changed files with 108 additions and 30 deletions
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22
3B2/3b2_cpu.c
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@@ -2127,6 +2127,11 @@ t_stat sim_instr(void)
break;
case BRB:
pc_incr = sign_extend_b(dst->embedded.b);
/* BRB is commonly used to halt the processor in a tight
* infinite loop. */
if (pc_incr == 0) {
stop_reason = STOP_LOOP;
}
break;
case BSBH:
cpu_push_word(R[NUM_PC] + pc_incr);
@@ -2554,7 +2559,7 @@ t_stat sim_instr(void)
}
break;
case STREND:
while (read_b(R[0], ACC_AF) != 0) {
while (read_b(R[0], ACC_AF) != '\0') {
R[0]++;
}
break;
@@ -2907,7 +2912,6 @@ t_stat sim_instr(void)
pc_incr = 0;
break;
case SPOP:
sim_debug(TRACE_DBG, &cpu_dev, "SPOP\n");
/* Memory fault is signaled when no support processor is
active */
if (mau_broadcast(coprocessor_word, 0, 0) != SCPE_OK) {
@@ -2917,7 +2921,6 @@ t_stat sim_instr(void)
case SPOPD2:
case SPOPS2:
case SPOPT2:
sim_debug(TRACE_DBG, &cpu_dev, "SPOP{D|S|T}2\n");
a = cpu_effective_address(src1);
b = cpu_effective_address(dst);
if (mau_broadcast(coprocessor_word, a, b) != SCPE_OK) {
@@ -2927,7 +2930,6 @@ t_stat sim_instr(void)
case SPOPRD:
case SPOPRS:
case SPOPRT:
sim_debug(TRACE_DBG, &cpu_dev, "SPOPR{D|S|T}\n");
a = cpu_effective_address(src1);
if (mau_broadcast(coprocessor_word, a, 0) != SCPE_OK) {
cpu_abort(NORMAL_EXCEPTION, EXTERNAL_MEMORY_FAULT);
@@ -2936,7 +2938,6 @@ t_stat sim_instr(void)
case SPOPWD:
case SPOPWS:
case SPOPWT:
sim_debug(TRACE_DBG, &cpu_dev, "SPOPW{D|S|T}\n");
a = cpu_effective_address(dst);
if (mau_broadcast(coprocessor_word, 0, a) != SCPE_OK) {
cpu_abort(NORMAL_EXCEPTION, EXTERNAL_MEMORY_FAULT);
@@ -3017,9 +3018,16 @@ t_stat sim_instr(void)
R[NUM_FP] = R[NUM_SP];
break;
case STRCPY:
a = 0;
while ((a = read_b(R[0], ACC_AF)) != '\0') {
/* The STRCPY instruction will always copy the NULL
* terminator of a string. However, copying the NULL
* terminator never increments the source or destination
* pointer! */
while (1) {
a = read_b(R[0], ACC_AF);
write_b(R[1], (uint8) a);
if (a == '\0') {
break;
}
R[0]++;
R[1]++;
}