165 lines
4.3 KiB
C
165 lines
4.3 KiB
C
/* This file is included into vb.c and cannot be compiled on its own. */
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#ifdef VBAPI
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/***************************** Callback Handlers *****************************/
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/* Prepare to handle an exception */
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#ifndef VB_DIRECT_LINK
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#define VB_ON_LINK sim1->onLink
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#else
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extern int VB_DIRECT_LINK(VB *, VB *, uint8_t *, uint8_t *);
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#define VB_ON_LINK VB_DIRECT_LINK
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#endif
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static int extOnLink(VB *sim1, VB *sim2, uint8_t *value1, uint8_t *value2) {
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return sim1->onLink != NULL && VB_ON_LINK(sim1, sim2, value1, value2);
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}
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#undef VB_ON_LINK
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/***************************** Library Functions *****************************/
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/* Process component */
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static int extEmulate(VB *sim, uint32_t clocks) {
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VB *peer; /* Communication peer */
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VB *sims[2]; /* Communication peers */
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uint8_t values[2]; /* Transmission values */
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int x; /* Iterator */
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/* Communication will not occur */
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if (!sim->ext.c_stat || sim->ext.c_clk_sel)
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return 0;
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/* Communication completes after time to process */
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if (sim->ext.clocks > clocks) {
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sim->ext.clocks -= clocks;
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return 0;
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}
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/* Exchange transmission data */
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sims [0] = sim;
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sims [1] = sim->peer;
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values[0] = sim->ext.cdtr;
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values[1] = sim->peer == NULL ? 0 : sim->peer->ext.cdtr;
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if (extOnLink(sim, sim->peer, &values[0], &values[1]))
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return 1;
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/* Update state */
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for (x = 0; x < 2; x++) {
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sim = sims[x];
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peer = sims[x ^ 1];
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if (sim == NULL)
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break;
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if (peer == NULL)
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peer = sim;
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/* Registers */
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sim->ext.cdrr = values[x ^ 1];
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sim->ext.c_irq |= !sim->ext.c_int_inh;
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sim->ext.c_stat = 0;
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sim->ext.cc_rd = sim->ext.cc_wr & peer->ext.cc_wr;
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sim->ext.cc_smp = sim->ext.cc_sig & peer->ext.cc_sig & sim->ext.cc_rd;
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sim->ext.cc_irq |= !sim->ext.cc_int_inh &&
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sim->ext.cc_smp == sim->ext.cc_int_lev;
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/* Interrupt */
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if (sim->ext.c_irq | sim->ext.cc_irq)
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sim->cpu.irq |= 0x0008;
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}
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return 0;
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}
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/* Read a value from CCR */
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static int32_t extReadCCR(VB *sim) {
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return 0x6D |
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sim->ext.c_int_inh << 7 |
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sim->ext.c_clk_sel << 4 |
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sim->ext.c_stat << 1
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;
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}
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/* Read a value from CCSR */
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static int32_t extReadCCSR(VB *sim) {
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sim->ext.cc_rd = sim->ext.cc_wr &
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(sim->peer == NULL ? 1 : sim->peer->ext.cc_wr);
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return 0x60 |
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sim->ext.cc_int_inh << 7 |
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sim->ext.cc_int_lev << 4 |
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sim->ext.cc_sig << 3 |
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sim->ext.cc_smp << 2 |
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sim->ext.cc_wr << 1 |
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sim->ext.cc_rd
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;
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}
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/* Simulate a hardware reset */
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static void extReset(VB *sim) {
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/* Normal */
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sim->ext.c_clk_sel = 0;
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sim->ext.c_int_inh = 0;
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sim->ext.c_stat = 0;
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sim->ext.cc_int_inh = 1;
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sim->ext.cc_int_lev = 1;
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sim->ext.cc_sig = 1;
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sim->ext.cc_wr = 1;
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sim->ext.cdrr = 0x00;
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sim->ext.cdtr = 0x00;
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/* Other */
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sim->ext.c_irq = 0;
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sim->ext.cc_irq = 0;
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}
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/* Determine how many clocks are guaranteed to process */
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static uint32_t extUntil(VB *sim, uint32_t clocks) {
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return !sim->ext.c_stat || sim->ext.c_clk_sel || clocks < sim->ext.clocks ?
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clocks : sim->ext.clocks;
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}
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/* Write a value to CCR */
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static void extWriteCCR(VB *sim, uint8_t value) {
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/* Configure state */
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sim->ext.c_int_inh = value >> 7 & 1;
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sim->ext.c_clk_sel = value >> 4 & 1;
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/* Acknowledge interrupt */
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if (sim->ext.c_int_inh) {
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sim->ext.c_irq = 0;
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if (!sim->ext.cc_irq)
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sim->cpu.irq &= ~0x0008;
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}
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/* Do not initiate a communication */
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if (sim->ext.c_stat || (value & 0x04) == 0) /* C-Start */
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return;
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/* Initiate a communication */
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sim->ext.c_stat = 1;
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sim->ext.clocks = 3200; /* 160us */
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}
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/* Write a value to CCSR */
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static void extWriteCCSR(VB *sim, uint8_t value) {
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/* Configure state */
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sim->ext.cc_int_inh = value >> 7 & 1;
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sim->ext.cc_int_lev = value >> 4 & 1;
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sim->ext.cc_sig = value >> 3 & 1;
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sim->ext.cc_wr = value >> 1 & 1;
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/* Acknowledge interrupt */
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if (!sim->ext.cc_int_inh)
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return;
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sim->ext.cc_irq = 0;
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if (!sim->ext.c_irq)
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sim->cpu.irq &= ~0x0008;
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}
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#endif /* VBAPI */
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